Name: a proteoliposome-based efflux assay to determine single-molecule properties of cl- channels and transporters
Uploaded: 2015-04-20T13:00:00.000+00:00
Duration: 7 min 47 s
Description: Watch this Scientific Journal Video about A Proteoliposome-Based Efflux Assay to Determine Single-molecule Properties of Cl- Channels and Transporters at JoVE.com

This work was supported by NIH grant GM085232 and an Irma T. Hirschl/ Monique Weill-Caulier Scholar Award (to A.A.).

1. 지질 준비 <ol><li> 투명 유리 튜브로 원하는 양의 지질 나누어지는. 사용 E. 콜라이 극성 지질 추출물하지만 대부분 지질 조성물을 사용할 수있다. 지질이 분말 형태 인 경우, 20 ㎎ / ㎖의 농도로 이들을 클로로포름에 재현 탁. 모든 용매가 증발 할 때까지 N 2 가스에서 RT에서 지질을 건조. </li><li> 펜탄의 지질을 재현 탁 클로로포름의 남은 흔적을 제거하기 위해 다시 가스 N 2를 일정하게 건조시킨다. 드라이 모든 용매를 증발 할 때까지. 건조 동안 지질이 아래쪽 형성 치밀한 질량보다는 튜브의 아래쪽을 덮는 제 균일 한 막 분포되도록 부드럽게 회전 튜브. </li><li> 재구성 버퍼 함유 세제를 추가 (300 mM의 KCl을 50 mM의 시트르산, 25 mM의 K 2 HPO 4의 pH 4.5, 35 mM의 CHAPS)은 지질을 용해. 단백질이 CHAPS에 가난하게 허용하는 경우이 단계에서 다른 중성 세제를 사용하십시오. </li><li> Resuspen물 목욕 초음파기를 사용하여 선명도 지질 거라고. 짧은 (30 초 - 1 분)와 짧은 (30 초 - 1 분) 펄스를 최대 전력에서 물 초음파기 목욕의 중심에 튜브를 담가 일시 중지합니다. 이 솔루션은 명확하게해야한다. 주 : 최종 명확성 정도 달성​​ 사용될 특정 지질 조성에 의존한다. 심지어 동일한 명목상 지질이 단계 중 일부 뱃치 간 변이는 것도 가능하다. 잔류 헤이즈를 원심 분리에 의해 제거 될 수 현탁액 중의 큰 입자에 의한 광의 산란에 기인한다. </li><li> 20 ~ 60 분 동안 실온에서 재현 탁 지질을 품어. </li></ol> 2. Proteoliposome 형성 주 : 몇 가지 전략은 리포좀으로 세제 용해 된 단백질을 삽​​입하기 위해 사용될 수있다. CLC-EC1은 투석은 잘 작동하기 때문에 선택 6,9,10의 방법이다. <ol><li> 로 정제 된 단백질을 추가 원하는 단백질로 지질 μg의 O를 표현 (P / L) 비율 (<html> F 단백질 / mg의 지질). P / L 비의 선택은 실험의 목적에 의존한다. <ol><li> 목표는 관심있는 단백질의 활성을 평가 높은 P에 재구성하는 경우 각 리포좀 단백질의 여러 복사본을 포함합니다 / L&#39;들, 신호를 최대화한다. 각 소포 평균 한 단백질에 포함되도록 활성 및 / 또는 단백질의 단일 전송 레이트를 수치화하기 위해, 낮은 P / L&#39; s의 포아송 희석 정권 재구성한다. 각 체제를 사용하는 경우보다 깊이 분석을위한 7 단계 및 토론을 참조하십시오. </li></ol></li><li> 다양한 섭생에 대한 최적의 P / L 값을 결정하려면, 8,11-13 단백질 농도의 함수로서 활성의 완전한 적정을 수행한다. 그러나, 활성 단위의 분자량 (MW가 kDa의 표시)하는 모든 단백질을 다음 P / ℓ를 초기 값을 절반으로 사용될 수있는 공지되어있다 : PG &quot;/&gt; <img alt="식 (2)" fo:content-width="1.5in" src="/files/ftp_upload/52369/52369eq2.jpg" /></li><li> 미리 유체 접촉 투석 튜브 또는 카세트에 단백질과 지질 혼합물을로드합니다. 500-1,000x 지질 재구성 버퍼의 양을 함유하는 비이커에 투석 장치를 배치 (즉, 지질 부유 1 ㎖를 1 L 버퍼) 부드러운 교반하에. <ol><li> 변경 버퍼 간격&gt; 3 시간에 3-4 회. 모든 솔루션 변화에서, 카세트 / 튜브 및 증류수로 비커를 씻어 신선한 재구성 버퍼 비커를 입력합니다. 솔루션 변화 1-2 O / N 간격을 포함합니다. 용액 변경의 정확한 수와 기간이 사용될 정확한 지질 및 세제에 의존한다. </li></ol></li><li> 마지막 단계가 완료된 후, 투석 용기로부터 제거 리포좀 튜브들을 분취 플래시 -80 ° C에서 액상이 N 또는 동결 그들을 동결. </li></ol> 3. 녹화 환경 &lt;P 클래스 = &quot;jove_content&quot;&gt; 참고 : 녹화 설정 (그림 2A)이 두 개의 챔버 (평면 바닥 실린더, ~ 3-4 ml의 부피), CL로 구성 - 전극, 아날로그와 pH 측정기 (아래 참조) 디지털 전기 출력, 디지타이저 및 적절한 수집 소프트웨어와 컴퓨터 나. <ol><li> pH 미터 전극을, 컴퓨터에 연결되어 디지타이저 pH 미터의 출력 - CL을 연결한다. 하나의 챔버에서 기준 전극과 다른 (그림 2B)에서 레코딩 와이어를 놓습니다. 주 : 칼 ΔV가 양수 (단계 6.4 및 7.2 참조)의 경우에는 와이어 극성이 맞는지. </li><li> 기록 챔버 (그림 1B)에서 교반 막대와 볶음 접시에 챔버를 놓습니다. 교반 막대를 전극에 접촉하지 않도록하십시오. </li><li> 한천 다리 (그림 2B) (100 mM의 KCl을 2 % 아가로 오스)를 사용하여 챔버를 연결합니다. 100 mM의 KCl을의 한천 다리를 저장합니다. </리&gt; </ol> CL 4. 준비 - 전극 <ol><li> 과거와 -possibly- 작동하지 않는 pH 전극을 가져 가라. 완전히 실버 와이어를 공개 유리막 브레이크. </li><li> 조심스럽게 메스 블레이드를 사용하여 실버 와이어에서 코팅을 제거합니다. H 2 O와의 EtOH 풍부한 양을 사용하여 와이어를 청소합니다. </li><li> 전선까지 50ml을 (또는 표백제)의 포화 용액에 장소의 AgCl의 균일 한 어두운 코트 덮여있다. </li></ol> 단일 층 소포 5. 준비 <ol><li> 실험 전에 밤, 외부 버퍼 15 ㎖ (1 ㎜의 KCl, SO 4, 25 mM의 구연산, 산도 4.5 150 mM의 K 2) 흔들리는 부드러운와가 (저어하지 않음)에 세파 덱스 G-50 구슬의 1g 팽창 사용하기 전에 실온에서 최소 3 시간. 각 실험은 부어 구슬 ~ 3 ㎖가 필요합니다. 기껏해야 몇 일 동안 4 ° C에서 부어 구슬을 유지합니다. </li><li> 리포좀을 실온에서 해동하는 동안, 각 열 ~ 3m 부어부어 G-50 구슬의 리터. RT 중력 흐름에 의해 그들을 말리면; 이것은 일반적으로 1 ~ 2 분 걸립니다. </li><li> 0.4 m 테플론 차단을 사용하여 미니 압출기를 통해 테오에게 11 번을 돌출시켜 단일 층 소포를 준비합니다. </li><li> 플라스틱 둥근 바닥 튜브에 열을 놓습니다. 여분의 용액을 제거하기 위해 열을 스핀. 임상 원심 분리기에서 1,400 XG에 20 ~ 30 초 동안 원심 분리기. </li><li> 13 X 100mm 유리 튜브의 흐름을 통해, 장소 열을 버리고 컬럼에 돌출 된 소포의 100 μl를 추가합니다. 임상 원심 분리기 500 XG에서 1 분 동안 열을 스핀. </li><li> 단계 6.5의 기록 챔버에 첨가한다 관류 ~ 200 μL의 수집. </li></ol> 6. 유출 측정 <ol><li> 레퍼런스 (접지) 100mm의 챔버의 KCl 2㎖ 및 외부 버퍼의 1.8 ml의 배치 (1 mM의 KCl을을 150 mM의 K 2 SO 4, 25 mM의 시트르산, pH를 4.5) 기록 챔버. 내부 사이의 약간의 삼투압의 불균형외부 솔루션에 영향을주지 않습니다 </li><li> 취득 프로그램을 시작합니다. 이 몇 분 정도 걸릴 수 있습니다, 기준이 평형을 보자. </li><li> 신호를 안정적으로 기준선 (리포좀 준비하고 건조 컬럼)에 도달하면 (도 3a)을 촬영을 시작. </li><li> 시스템 (그림 2A)를 교정 된 10 mM의 KCl 용액 15 μl를 추가합니다. </li><li> 리포좀을 추가합니다. 테오 (그림 3A)에서 - 작은 점프 인해 외부 CL의 불완전한 제거로 볼 수 있습니다. 베이스 라인이 안정 될 때까지 기다립니다. </li><li> 발리 노마 이신 (Valinomycin) 추가 (1 mg의 EtOH 중 / ㎖에서 1 μL)은 유출 (그림 3A)를 시작합니다. </li><li> 유출은 시간 물론 고원까지 (그림 3A)를 실행하자. </li><li> 모든 리포좀 (그림 3A)을 용해 할 수있는 외부 버퍼에 준비 1.5 M β-옥틸 글루코 시드 (β-OG)의 40 μl를 추가합니다. 촬영을 완료합니다. </li></ol> 7. 데이터nalysis <ol><li> ASCII 또는 텍스트 형식에서 추적 파일을 내보내고 선택의 분석 프로그램으로 가져옵니다. </li><li> 다음 사항 (도 3A)에서 전압을 측정한다 : 기록의 시작시 (0 V); 교정 펄스 (CAL V)을 첨가 한 후; 리포좀 (리포의 V)을 첨가 한 후; 유출 (V 지느러미)의 끝에; 세제 (V 어린 아이)을 첨가 한 후, 기준 전압 그래서 V 0 = 0. </li><li> 실험의 값을 결정 네른스트 - 플랑크 식을 사용하여 <img alt="식 (3)" fo:content-width=".3in" src="/files/ftp_upload/52369/52369eq3.jpg" /> 측정하여 <img alt="수학 식 4" fo:content-width="3in" src="/files/ftp_upload/52369/52369eq4.jpg" /> 여기서 권 칼 μL의 교정 펄스의 부피로 표현 된 실험의 시작에서 챔버 체적은 1800이다1 - 교정 펄스와 mm 단위로 외부 버퍼의 농도 ΔV CAL은 교정 펄스 후에 측정 MV에서 점프입니다 난, [CL] CAL /에서하면 CL 있습니다. 참고 : α의이 경험적인 결정은 세 가지 목적을 수행합니다 : 그것은 시스템이 제대로 응답하는지 보장, 실험 사이에 악기의 응답의 일관성의 측정을 제공뿐만 아니라 실수는 솔루션 결정에 만든되지 않았 음을 확인합니다. </li><li> 다음 각 단계 후에 CL 농도를 계산한다 : <img alt="식 (5)" fo:content-width="3.5in" src="/files/ftp_upload/52369/52369eq5.jpg" /> <img alt="식 (6)" fo:content-width="3.5in" src="/files/ftp_upload/52369/52369eq6.jpg" /> <img alt="식 (7)" fo:content-width="3.5in" src="/files/ftp_upload/52369/52369eq7.jpg" /> 400분의 3 인자는 2000 μL의 최종 부피로 15 μL 교정 펄스의 희석에서 온다. </li><li> Calcul각 단계, 지느러미 ΔCl의 사러가 / / TOT에서 [CL]의 변화를 먹었다. </li><li> 와 CL (t)에 V (t)를 변환 <img alt="식 (8)" fo:content-width="3.5in" src="/files/ftp_upload/52369/52369eq8.jpg" /> 직접 중요한 지점에서 [CL] 값을 결정하고 내부 통제로 계산 된 값으로 비교합니다. </li><li> 추적을 정상화 CL 확인해의 리포 = 0, CL 확인해 무비 = 1 그래서 <img alt="식 (9)" fo:content-width="3.5in" src="/files/ftp_upload/52369/52369eq9.jpg" /></li><li> 하기 식 유출 경시 맞는 : <img alt="식 (10)" fo:content-width="3.5in" src="/files/ftp_upload/52369/52369eq10.jpg" /> CL 실험적으로 측정함으로써 결정된다 누설 - - L는 Cl의 비율이다 τ와 동일한 조건에서 제조 된 무 단백질 리포좀으로부터 유출이 공정의 시간 상수이다. </li><li> V, 초기 속도를 계산한다 : 여기서 ΔCl 핀은 밀리몰의 표현 및 V는 μL의 챔버의 체적이다. </li><li> 전송 속도 / 전도도를 계산 <img alt="식 (12)" fo:content-width="3.5in" src="/files/ftp_upload/52369/52369eq12.jpg" /> P는 P / L이고, MW는 활성 착물 ​​kDa의 분자량으로 표현 </li></ol>

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A., MacKinnon, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Functional+reconstitution+of+purified+human+Hv1+H++channels.">Functional reconstitution of purified human Hv1 H+ channels.</a> Journal of Molecular Biology. 387, 1055-1060 (2009).</li><li>Terashima, H., Picollo, A., Accardi, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Purified+TMEM16A+is+sufficient+to+form+Ca2++activated+Cl-+channels.">Purified TMEM16A is sufficient to form Ca2+ activated Cl- channels.</a> Proc Natl Acad Sci U S A. 110, 19354-19359 (2013).</li><li>Malvezzi, M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Ca2+-dependent+phospholipid+scrambling+by+a+reconstituted+TMEM16+ion+channel.">Ca2+-dependent phospholipid scrambling by a reconstituted TMEM16 ion channel.</a> Nature Communications. 4, 2367 (2013).</li><li>Picollo, A., Malvezzi, M., Houtman, J. C., Accardi, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Basis+of+substrate+binding+and+conservation+of+selectivity+in+the+CLC+family+of+channels+and+transporters.">Basis of substrate binding and conservation of selectivity in the CLC family of channels and transporters.</a> Nat Struct Mol Biol. 16, 1294-1301 (2009).</li><li>Eckford, P. D., Li, C., Ramjeesingh, M., Bear, C. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cystic+fibrosis+transmembrane+conductance+regulator+(CFTR)+potentiator+VX-770+(ivacaftor)+opens+the+defective+channel+gate+of+mutant+CFTR+in+a+phosphorylation-dependent+but+ATP-independent+manner.">Cystic fibrosis transmembrane conductance regulator (CFTR) potentiator VX-770 (ivacaftor) opens the defective channel gate of mutant CFTR in a phosphorylation-dependent but ATP-independent manner.</a> J Biol Chem. 287, 36639-36649 (2012).</li><li>Stockbridge, R. B., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Fluoride+resistance+and+transport+by+riboswitch-controlled+CLC+antiporters.">Fluoride resistance and transport by riboswitch-controlled CLC antiporters.</a> Proc Natl Acad Sci U S A. 109, 15289-15294 (2012).</li><li>Menon, I., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Opsin+is+a+phospholipid+flippase.">Opsin is a phospholipid flippase.</a> Curr Biol. 21, 149-153 (2011).</li><li>Nimigean, C. M., Miller, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Na++block+and+permeation+in+a+K++channel+of+known+structure.">Na+ block and permeation in a K+ channel of known structure.</a> J Gen Physiol. 120, 323-335 (2002).</li><li>Picollo, A., Xu, Y., Johner, N., Bern&#232;che, S., Accardi, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Synergistic+substrate+binding+determines+the+stoichiometry+of+transport+of+a+prokaryotic+H(+)/Cl(-)+exchanger.">Synergistic substrate binding determines the stoichiometry of transport of a prokaryotic H(+)/Cl(-) exchanger.</a> Nat Struct Mol Biol. 19, 525-531 (2012).</li><li>Tsai, M. F., Fang, Y., Miller, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Sided+functions+of+an+arginine-agmatine+antiporter+oriented+in+liposomes.">Sided functions of an arginine-agmatine antiporter oriented in liposomes.</a> Biochemistry. 51, 1577-1585 (2012).</li><li>Heginbotham, L., Kolmakova-Partensky, L., Miller, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Functional+reconstitution+of+a+prokaryotic+K++channel.">Functional reconstitution of a prokaryotic K+ channel.</a> J Gen Physiol. 111, 741-749 (1998).</li><li>Lundbaek, J. A., Collingwood, S. A., Ing&#243;lfsson, H. I., Kapoor, R., Andersen, O. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Lipid+bilayer+regulation+of+membrane+protein+function:+gramicidin+channels+as+molecular+force+probes.">Lipid bilayer regulation of membrane protein function: gramicidin channels as molecular force probes.</a> J R Soc Interface. 7, 373-395 (2010).</li><li>Lim, H. H., Stockbridge, R. B., Miller, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Fluoride-dependent+interruption+of+the+transport+cycle+of+a+CLC+Cl(-)/H(+)+antiporter.">Fluoride-dependent interruption of the transport cycle of a CLC Cl(-)/H(+) antiporter.</a> Nat Chem Biol. 9, 712-715 (2013).</li><li>Stockbridge, R. B., Robertson, J. L., Kolmakova-Partensky, L., Miller, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+family+of+fluoride-specific+ion+channels+with+dual-topology+architecture.">A family of fluoride-specific ion channels with dual-topology architecture.</a> Elife. 2, e01084 (2013).</li><li>Nimigean, C., Shane, T., Miller, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+cyclic+nucleotide+modulated+prokaryotic+K++channel.">A cyclic nucleotide modulated prokaryotic K+ channel.</a> J Gen Physiol. 124, 7 (2004).</li><li>Brohawn, S. G., del M&#225;rmol, ., J, R., MacKinnon, <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Crystal+Structure+of+the+Human+K2P+TRAAK,+a+Lipid-+and+Mechano-Sensitive+K++Ion+Channel.">Crystal Structure of the Human K2P TRAAK, a Lipid- and Mechano-Sensitive K+ Ion Channel.</a> Science. 335, 436-441 (2012).</li><li>Jayaram, H., Robertson, J. L., Wu, F., Williams, C., Miller, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Structure+of+a+slow+CLC+Cl-/H++antiporter+from+a+cyanobacterium.">Structure of a slow CLC Cl-/H+ antiporter from a cyanobacterium.</a> Biochemistry. 50, 788-794 (2011).</li></ol>

The authors declare no competing financial interests.

정제 음이온 선택적 채널 또는 리포좀에 재구성 수송에 의해 매개 교통 - 우리는 상세한 CL을 측정 할 수있는 프로토콜을 설명했다. CLC-EC1을 기 - 사용 된 예는 원핵 H + / CL이었다. 고려중인 이온에 적합한 하나의 AgCl 전극 : 그러나, 방법론 용이 리간드 12,13,15, 11,12 전압 또는 AG로 대체하여 다른 음이온 선택성 15,16 스포츠 의해 게이트 된 채널을 연구하기에 ?...

마지막 두 과발현과 막 수송 단백질을 정제 할 수있는 능력이 크게 증가하고있다 수십 년 : 이온 채널, 일차 및 이차 전송기들은 보통 이종 발현 시스템뿐만 아니라, 천연 공급원으로부터 정제된다. 이 단백질의 안정성을, 표현을 모니터링 개선하고 추출을 용이하게하고 강화하는 새로운 접근 방식은 끊임없이 1-5 개발되고있다. 이러한 기술 혁신은 차례로, 그 기능의 구조적 기지에 대한 우리의 이해를 강화, 막 단백질에 원자 수준의 구조 정보의 폭발을 유발하는 데 큰 도움이되고있다. 반면에, 우리의 능력은 어떤 경우에는 고해상도 구조적 정보가 따라서 정량적 구조 기반 예측을 테스트 할 수있는 능력을 제한 질적 기능 데이터에 의해 수반되도록, 동일한 비율로 증가하지 않은 정제 된 단백질의 기능적 특성을 프로빙. 따라서, developmen는양적 일반화 기능 분석의 t는 막 단백질의 기능 기계론 토대 해명 향해 중요한 단계이다. 채널 및 전송기 - 준비 정량적 정제하고 재구성 CL의 주요 기능적 특성을 결정하기 위해 사용될 수 유출 분석을 기술한다. 분석을위한 원칙은 교통 시스템뿐만 아니라 다양한 비 이온 수송 단백질로 일반화 될 수있다. 채널 / CL 대형의 존재 수송차 - - 정제 된 리포솜 CL로 녹이고 구배 (도 1A, B). CL이 - 유출가 우리의 경우에는, 반대 이온 플럭스 있도록 이온 운반체의 첨가에 의해 개시되는 K + 이온 운반체 발리 노마 이신 (Valinomycin), CL에 의해 설정된 전압 션트되는 - 구배 및 K의 평형 전위로 초기 막 전위를 설정할 + 6,7. t없이이 횡단 전위의 발생에 의해 방지로 유출이 발생, - 그는 더 중요한 순 (CL)을 이온 운반체가 없습니다. - 유출 및 F 0, 활성 단백질을 함유하지 않은 리포좀 분획 τ, CL의 시상수 : 정량적 데이터는 두 개의 측정 파라미터 (도 1C)에 의해 설명된다. τ와 f 0 CL에서 단일 - 전송 속도, 활성 단백질의 활성 분획물 및 복합체의 분자량은 8 유도 될 수있다. 알려진 구조와 기능의 교환기 -이 기술은 CLC-EC1, 잘 특성화 된 CLC 형 H + / CL로 재구성 테오를 사용하여 여기에 예시되어있다. 상기 분석 용이 전압 활성 및 / 또는 리간드의 존재에 따라 상이한 또는 이온 선택성 채널들 또는 컨베이어로 일반화된다. 또한,이 분석은 소분자 직접 영향을 미치는 단백질 재구성 여부를 결정하는데 사용될 수있다,이들 화합물 및 방법에 막 조성물 또는 지질 - 변경 시약 재구성 채널들 및 수송의 기능에 영향을 미치는 영향을 정량.

<table><tbody><tr><td>Liposomicator, Avanti Polar Lipids Inc.</td><td>&amp;nbsp;Avanti Polar Lipids Inc.</td><td>610200</td><td></td></tr><tr><td>IEC Centra CL2 Benchtop</td><td>Thermo Scientific</td><td></td><td></td></tr><tr><td>Orion Research Model 701A Digital pH-mV meter</td><td></td><td></td><td>These can be found on Ebay.</td></tr><tr><td>Non-functional pH probe</td><td></td><td></td><td>Any pH meter probe with silver wires will work. The glass/plastic coating needs to be removed and the wires cleaned.</td></tr><tr><td>DI-710 Data Logger</td><td>DATAQ instruments</td><td></td><td></td></tr><tr><td>WinDAQ acquisition software</td><td>DATAQ instruments</td><td></td><td></td></tr><tr><td>Pierce Disposable Plastic Columns, Gravity-flow, 2ml</td><td>Pierce (Thermo Scientific)</td><td>29922</td><td></td></tr><tr><td>KIMAX Culture Tubes, Disposable, Borosilicate Glass</td><td>Kimble Chase</td><td>73500-13100</td><td></td></tr><tr><td>Extruder Set With Holder/Heating Block</td><td>Avanti Polar Lipids Inc.</td><td>610000</td><td></td></tr><tr><td>Computer</td><td></td><td></td><td></td></tr></tbody></table>

a proteoliposome-based efflux assay to determine single-molecule properties of cl- channels and transporters

The last 15 years have been characterized by an explosion in the ability to overexpress and purify membrane proteins from prokaryotic organisms as well as from eukaryotes. This increase has been largely driven by the successful push to obtain structural information on membrane proteins. However, the ability to functionally interrogate these proteins has not advanced at the same rate and is often limited to qualitative assays of limited quantitative value, thereby limiting the mechanistic insights that they can provide. An assay to quantitatively investigate the transport activity of reconstituted Cl- channels or transporters is described. The assay is based on the measure of the efflux rate of Cl- from proteoliposomes following the addition of the K+ ionophore valinomycin to shunt the membrane potential. An ion sensitive electrode is used to follow the time-course of ion efflux from proteoliposomes reconstituted with the desired protein. The method is highly suited for mechanistic studies, as it allows for the quantitative determination of key properties of the reconstituted protein, such as its unitary transport rate, the fraction of active protein and the molecular mass of the functional unit. The assay can also be utilized to determine the effect of small molecule compounds that directly inhibit/activate the reconstituted protein, as well as to test the modulatory effects of the membrane composition or lipid-modifying reagents. Where possible, direct comparison between results obtained using this method were found to be in good agreement with those obtained using electrophysiological approaches. The technique is illustrated using CLC-ec1, a CLC-type H+/Cl- exchanger, as a model system. The efflux assay can be utilized to study any Cl- conducting channel/transporter and, with minimal changes, can be adapted to study any ion-transporting protein.

교환기, 리포좀에 재구성 - 정제 CLC-EC1, 원핵 CLC 형 H + / CL에 의해 매개 교통 - 우리는 상세하고 강력한 CL을 측정 할 수있는 프로토콜을 설명합니다. 실험 장치의 개략적 인 대표도도 3에 도시되어 정제 된 CLC-EC1 및 높은 내부 CL 함유 재구성은 테오 -. 낮은 CL 함유 용액 욕에 침지 -. 이러한 조건 그물 CL에서 - 유출은 리포좀 (그림 3A)...

Watch this Scientific Journal Video about A Proteoliposome-Based Efflux Assay to Determine Single-molecule Properties of Cl- Channels and Transporters at JoVE.com

A Proteoliposome-Based Efflux Assay to Determine Single-molecule Properties of Cl- Channels and Transporters

Proteoliposomes are used to study purified channels and transporters reconstituted in a well-defined biochemical environment. An experimental procedure to measure efflux mediated by these proteins is illustrated. The steps to prepare proteoliposomes, perform the recordings, and analyze data to quantitatively determine the functional properties of the reconstituted protein are described.

Proteoliposome 기반 유출 분석은 CL의 단일 분자의 속성을 확인하는<sup&gt; -</sup&gt; 채널 및 전송기

The last 15 years have been characterized by an explosion in the ability to overexpress and purify membrane proteins from prokaryotic organisms as well as ...

a-proteoliposome-based-efflux-assay-to-determine-single-molecule

Universidad de Cartagena UDEC

Research

JoVE Journal

Biology

A Proteoliposome-Based Efflux Assay to Determine Single-molecule Properties of Cl- Channels and Transporters

9.8K 조회수.  Weill Cornell Medical College. Proteoliposomes are used to study purified channels and transporters reconstituted in a well-defined biochemical environment. An experimental procedure to measure efflux mediated by these proteins is illustrated. The steps to prepare proteoliposomes, perform the recordings, and analyze data to quantitatively determine the functional properties of the reconstituted protein are described.

비디오: A Proteoliposome-Based Efflux Assay to Determine Single-molecule Properties of Cl- Channels and Transporters

Cholesterol Efflux Assay

Cholesterol content of cells must be maintained within the very tight limits, too much or too little cholesterol in a cell results in disruption of cellular membranes, apoptosis and necrosis 1. Cells can source cholesterol from intracellular synthesis and from plasma lipoproteins, both sources are sufficient to fully satisfy cells' requirements for cholesterol. The processes of cholesterol synthesis and uptake are tightly regulated and deficiencies of cholesterol are rare 2. Excessive cholesterol is more common problem 3. With the exception of hepatocytes and to some degree adrenocortical cells, cells are unable to degrade cholesterol. Cells have two options to reduce their cholesterol content: to convert cholesterol into cholesteryl esters, an option with limited capacity as overloading cells with cholesteryl esters is also toxic, and cholesterol efflux, an option with potentially unlimited capacity. Cholesterol efflux is a specific process that is regulated by a number of intracellular transporters, such as ATP binding cassette transporter proteins A1 (ABCA1) and G1 (ABCG1) and scavenger receptor type B1. The natural acceptor of cholesterol in plasma is high density lipoprotein (HDL) and apolipoprotein A-I. 
The cholesterol efflux assay is designed to quantitate the rate of cholesterol efflux from cultured cells. It measures the capacity of cells to maintain cholesterol efflux and/or the capacity of plasma acceptors to accept cholesterol released from cells. The assay consists of the following steps. Step 1: labelling cellular cholesterol by adding labelled cholesterol to serum-containing medium and incubating with cells for 24-48 h. This step may be combined with loading of cells with cholesterol. Step 2: incubation of cells in serum-free medium to equilibrate labelled cholesterol among all intracellular cholesterol pools. This stage may be combined with activation of cellular cholesterol transporters. Step 3: incubation of cells with extracellular acceptor and quantitation of movement of labelled cholesterol from cells to the acceptor. If cholesterol precursors were used to label newly synthesized cholesterol, a fourth step, purification of cholesterol, may be required.
The assay delivers the following information: (i) how a particular treatment (a mutation, a knock-down, an overexpression or a treatment) affects the capacity of cell to efflux cholesterol and (ii) how the capacity of plasma acceptors to accept cholesterol is affected by a disease or a treatment. This method is often used in context of cardiovascular research, metabolic and neurodegenerative disorders, infectious and reproductive diseases.

The cholesterol assay is designed to quantitate the rate of cholesterol efflux from cultured cells and the capacity of plasma acceptors to accept cholesterol released from cells. The assay consists of labelling cells with cholesterol, equilibration of cholesterol among intracellular pools and release of cholesterol to an extracellular acceptor.

콜레스테롤 유출 분석

Cholesterol content of cells must be maintained within the very tight limits, too much or too little cholesterol in a cell results in disruption of ...

연구

의학

Models and Methods to Evaluate Transport of Drug Delivery Systems Across Cellular Barriers

Sub-micrometer carriers (nanocarriers; NCs) enhance efficacy of drugs by improving solubility, stability, circulation time, targeting, and release. Additionally, traversing cellular barriers in the body is crucial for both oral delivery of therapeutic NCs into the circulation and transport from the blood into tissues, where intervention is needed. NC transport across cellular barriers is achieved by: (i) the paracellular route, via transient disruption of the junctions that interlock adjacent cells, or (ii) the transcellular route, where materials are internalized by endocytosis, transported across the cell body, and secreted at the opposite cell surface (transyctosis). Delivery across cellular barriers can be facilitated by coupling therapeutics or their carriers with targeting agents that bind specifically to cell-surface markers involved in transport. Here, we provide methods to measure the extent and mechanism of NC transport across a model cell barrier, which consists of a monolayer of gastrointestinal (GI) epithelial cells grown on a porous membrane located in a transwell insert. Formation of a permeability barrier is confirmed by measuring transepithelial electrical resistance (TEER), transepithelial transport of a control substance, and immunostaining of tight junctions. As an example, ~200&#160;nm polymer NCs are used, which carry a therapeutic cargo and are coated with an antibody that targets a cell-surface determinant. The antibody or therapeutic cargo is labeled with 125I for radioisotope tracing and labeled NCs are added to the upper chamber over the cell monolayer for varying periods of time. NCs associated to the cells and/or transported to the underlying chamber can be detected. Measurement of free 125I allows subtraction of the degraded fraction. The paracellular route is assessed by determining potential changes caused by NC transport to the barrier parameters described above. Transcellular transport is determined by addressing the effect of modulating endocytosis and transcytosis pathways.

Many therapeutic applications require safe and efficient transport of drug carriers and their cargoes across cellular barriers in the body. This article describes an adaptation of established methods to evaluate the rate and mechanism of transport of drug nanocarriers (NCs) across cellular barriers, such as the gastrointestinal (GI) epithelium.

모델 및 세포 장벽에 걸쳐 약물 전달 시스템의 전송을 평가하는 방법

Sub-micrometer carriers (nanocarriers; NCs) enhance efficacy of drugs by improving solubility, stability, circulation time, targeting, and release. ...

생체공학

Single Liposome Measurements for the Study of Proton-Pumping Membrane Enzymes Using Electrochemistry and Fluorescent Microscopy

Proton-pumping enzymes of electron transfer chains couple redox reactions to proton translocation across the membrane, creating a proton-motive force used for ATP production. The amphiphilic nature of membrane proteins requires particular attention to their handling, and reconstitution into the natural lipid environment is indispensable when studying membrane transport processes like proton translocation. Here, we detail a method that has been used for the investigation of the proton-pumping mechanism of membrane redox enzymes, taking cytochrome bo3 from Escherichia coli as an example. A combination of electrochemistry and fluorescence microscopy is used to control the redox state of the quinone pool and monitor pH changes in the lumen. Due to the spatial resolution of fluorescent microscopy, hundreds of liposomes can be measured simultaneously while the enzyme content can be scaled down to a single enzyme or transporter per liposome. The respective single enzyme analysis can reveal patterns in the enzyme functional dynamics that might be otherwise hidden by the behavior of the whole population. We include a description of a script for automated image analysis.

Here, we present a protocol to study the molecular mechanism of proton translocation across lipid membranes of single liposomes, using cytochrome bo3 as an example. Combining electrochemistry and fluorescence microscopy, pH changes in the lumen of single vesicles, containing single or multiple enzyme, can be detected and analyzed individually.

전기 화학 및 형광 현미경 검사 법을 사용 하 여 양성자 펌프 막 효소의 연구에 대 한 단일 Liposome 측정

Proton-pumping enzymes of electron transfer chains couple redox reactions to proton translocation across the membrane, creating a proton-motive force used ...

생화학

Selection of Transporter-Targeted Inhibitory Nanobodies by Solid-Supported-Membrane (SSM)-Based Electrophysiology

Single domain antibodies (nanobodies) have been extensively used in mechanistic and structural studies of proteins and they pose an enormous potential as tools for developing clinical therapies, many of which depend on the inhibition of membrane proteins such as transporters. However, most of the methods used to determine the inhibition of transport activity are difficult to perform in high-throughput routines and depend on labeled substrates availability thereby complicating the screening of large nanobody libraries. Solid-supported membrane (SSM) electrophysiology is a high-throughput method, used for characterizing electrogenic transporters and measuring their transport kinetics and inhibition. Here we show the implementation of SSM-based electrophysiology to select inhibitory and non-inhibitory nanobodies targeting an electrogenic secondary transporter and to calculate nanobodies inhibitory constants. This technique may be especially useful for selecting inhibitory nanobodies targeting transporters for which labeled substrates are not available.

Selection of Transporter-Targeted Inhibitory Nanobodies by Solid-Supported-Membrane SSM-Based Electrophysiology

Nanobodies are important tools in structural biology and pose a great potential for the development of therapies. However, the selection of nanobodies with inhibitory properties can be challenging. Here we demonstrate the use of solid-supported-membrane (SSM)-based electrophysiology for the classification of inhibitory and non-inhibitory nanobodies targeting electrogenic membrane transporters.

고체 지원 멤브레인(SSM) 기반 전기생리학에 의한 수송기 표적 억제 나노체 선택

Single domain antibodies (nanobodies) have been extensively used in mechanistic and structural studies of proteins and they pose an enormous potential as ...

Gramicidin-based Fluorescence Assay; for Determining Small Molecules Potential for Modifying Lipid Bilayer Properties

Many drugs and other small molecules used to modulate biological function are amphiphiles that adsorb at the bilayer/solution interface and thereby alter lipid bilayer properties. This is important because membrane proteins are energetically coupled to their host bilayer by hydrophobic interactions. Changes in bilayer properties thus alter membrane protein function, which provides an indirect way for amphiphiles to modulate protein function and a possible mechanism for "off-target" drug effects. We have previously developed an electrophysiological assay for detecting changes in lipid bilayer properties using linear gramicidin channels as probes 3,12. Gramicidin channels are mini-proteins formed by the transbilayer dimerization of two non-conducting subunits. They are sensitive to changes in their membrane environment, which makes them powerful probes for monitoring changes in lipid bilayer properties as sensed by bilayer spanning proteins. We now demonstrate a fluorescence assay for detecting changes in bilayer properties using the same channels as probes. The assay is based on measuring the time-course of fluorescence quenching from fluorophore-loaded large unilamellar vesicles due to the entry of a quencher through the gramicidin channels. We use the fluorescence indicator/quencher pair 8-aminonaphthalene-1,3,6-trisulfonate (ANTS)/Tl+ that has been successfully used in other fluorescence quenching assays 5,13. Tl+ permeates the lipid bilayer slowly 8 but passes readily through conducting gramicidin channels 1,14. The method is scalable and suitable for both mechanistic studies and high-throughput screening of small molecules for bilayer-perturbing, and potential "off-target", effects. We find that results using this method are in good agreement with previous electrophysiological results 12.

We introduce a fast fluorescence-based assay that monitors the rate of fluorescence quenching as a measure of gramicidin channel activity. The gramicidin channels are used as molecular force transducers to monitor changes in lipid bilayer properties as sensed by bilayer spanning proteins.

그램이시딘 기반의 형광 분석, 지질 이중층의 속성을 수정하는 작은 분자 잠재 결정

Many drugs and other small molecules used to modulate biological function are amphiphiles that adsorb at the bilayer/solution interface and thereby alter ...

생물학

A Quantitative Fluorescence Microscopy-based Single Liposome Assay for Detecting the Compositional Inhomogeneity Between Individual Liposomes

Most research employing liposomes as membrane model systems or drug delivery carriers relies on bulk read-out techniques and thus intrinsically assumes all liposomes of the ensemble to be identical. However, new experimental platforms able to observe liposomes at the single-particle level have made it possible to perform highly sophisticated and quantitative studies on protein-membrane interactions or drug carrier properties on individual liposomes, thus avoiding errors from ensemble averaging. Here we present a protocol for preparing, detecting, and analyzing single liposomes using a fluorescence-based microscopy assay, facilitating such single-particle measurements. The setup allows for imaging individual liposomes in a massive parallel manner and is employed to reveal intra-sample size and compositional inhomogeneities. Additionally, the protocol describes the advantages of studying liposomes at the single liposome level, the limitations of the assay, and the important features to be considered when modifying it to study other research questions.

This protocol describes the fabrication of liposomes and how these can be immobilized on a surface and imaged individually in a massive parallel manner using fluorescence microscopy. This allows for the quantification of the size and compositional inhomogeneity between single liposomes of the population.

개별 리포좀 간의 조성 불균질성을 검출하기 위한 정량적 형광 현미경 검사법 기반 단일 리포좀 분석

Most research employing liposomes as membrane model systems or drug delivery carriers relies on bulk read-out techniques and thus intrinsically assumes ...

High-throughput Screening for Small-molecule Modulators of Inward Rectifier Potassium Channels

Specific members of the inward rectifier potassium (Kir) channel family are postulated drug targets for a variety of disorders, including hypertension, atrial fibrillation, and pain1,2. For the most part, however, progress toward understanding their therapeutic potential or even basic physiological functions has been slowed by the lack of good pharmacological tools. Indeed, the molecular pharmacology of the inward rectifier family has lagged far behind that of the S4 superfamily of voltage-gated potassium (Kv) channels, for which a number of nanomolar-affinity and highly selective peptide toxin modulators have been discovered3. The bee venom toxin tertiapin and its derivatives are potent inhibitors of Kir1.1 and Kir3 channels4,5, but peptides are of limited use therapeutically as well as experimentally due to their antigenic properties and poor bioavailability, metabolic stability and tissue penetrance. The development of potent and selective small-molecule probes with improved pharmacological properties will be a key to fully understanding the physiology and therapeutic potential of Kir channels.
The Molecular Libraries Probes Production Center Network (MLPCN) supported by the National Institutes of Health (NIH) Common Fund has created opportunities for academic scientists to initiate probe discovery campaigns for molecular targets and signaling pathways in need of better pharmacology6. The MLPCN provides researchers access to industry-scale screening centers and medicinal chemistry and informatics support to develop small-molecule probes to elucidate the function of genes and gene networks. The critical step in gaining entry to the MLPCN is the development of a robust target- or pathway-specific assay that is amenable for high-throughput screening (HTS).
Here, we describe how to develop a fluorescence-based thallium (Tl+) flux assay of Kir channel function for high-throughput compound screening7,8,9,10.The assay is based on the permeability of the K+ channel pore to the K+ congener Tl+. A commercially available fluorescent Tl+ reporter dye is used to detect transmembrane flux of Tl+ through the pore. There are at least three commercially available dyes that are suitable for Tl+ flux assays: BTC, FluoZin-2, and FluxOR7,8. This protocol describes assay development using FluoZin-2. Although originally developed and marketed as a zinc indicator, FluoZin-2 exhibits a robust and dose-dependent increase in fluorescence emission upon Tl+ binding. We began working with FluoZin-2 before FluxOR was available7,8 and have continued to do so9,10. However, the steps in assay development are essentially identical for all three dyes, and users should determine which dye is most appropriate for their specific needs. We also discuss the assay's performance benchmarks that must be reached to be considered for entry to the MLPCN. Since Tl+ readily permeates most K+ channels, the assay should be adaptable to most K+ channel targets.

Methods for developing and validating a quantitative fluorescence assay for measuring the activity of inward rectifier potassium (Kir) channels for high-throughput compound screening is presented.

안쪽 정류기의 칼륨 채널의 소형 분자 변조기에 대한 높은 처리량 검사

Specific members of the inward rectifier potassium (Kir) channel family are postulated drug targets for a variety of disorders, including hypertension, ...

In vitro Investigation of the MexAB Efflux Pump From Pseudomonas aeruginosa

There is an emerging scientific need for reliable tools for monitoring membrane protein transport. We present a methodology leading to the reconstitution of efflux pumps from the Gram-negative bacteria Pseudomonas aeruginosa in a biomimetic environment that allows for an accurate investigation of their activity of transport. Three prerequisites are fulfilled: compartmentation in a lipidic environment, use of a relevant index for transport, and generation of a proton gradient. The membrane protein transporter is reconstituted into liposomes together with bacteriorhodopsin, a light-activated proton pump that generates a proton gradient that is robust as well as reversible and tunable. The activity of the protein is deduced from the pH variations occurring within the liposome, using pyranin, a pH-dependent fluorescent probe. We describe a step-by-step procedure where membrane protein purification, liposome formation, protein reconstitution, and transport analysis are addressed. Although they were specifically designed for an RND transporter, the described methods could potentially be adapted for use with any other membrane protein transporter energized by a proton gradient.

In vitro Investigation of the MexAB Efflux Pump From Pseudomonas aeruginosa

We present a protocol for the in vitro investigation of efflux pumps from Pseudomonas aeruginosa. This protocol allows for the generation of a robust, reversible, and tunable proton gradient within the liposome membrane and hence should be adaptable to any membrane protein energized by the protomotive force.

녹농균에서 MexAB 유출 펌프의 체외 조사

There is an emerging scientific need for reliable tools for monitoring membrane protein transport. We present a methodology leading to the reconstitution ...

Functional Reconstitution and Channel Activity Measurements of Purified Wildtype and Mutant CFTR Protein

The Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) is a unique channel-forming member of the ATP Binding Cassette (ABC) superfamily of transporters. The phosphorylation and nucleotide dependent chloride channel activity of CFTR has been frequently studied in whole cell systems and as single channels in excised membrane patches. Many Cystic Fibrosis-causing mutations have been shown to alter this activity. While a small number of purification protocols have been published, a fast reconstitution method that retains channel activity and a suitable method for studying population channel activity in a purified system have been lacking. Here rapid methods are described for purification and functional reconstitution of the full-length CFTR protein into proteoliposomes of defined lipid composition that retains activity as a regulated halide channel. This reconstitution method together with a novel flux-based assay of channel activity is a suitable system for studying the population channel properties of wild type CFTR and the disease-causing mutants F508del- and G551D-CFTR. Specifically, the method has utility in studying the direct effects of phosphorylation, nucleotides and small molecules such as potentiators and inhibitors on CFTR channel activity. The methods are also amenable to the study of other membrane channels/transporters for anionic substrates.

Described here is a rapid and effective procedure for functional reconstitution of purified wild-type and mutant CFTR protein that preserves activity for this chloride channel, which is defective in Cystic Fibrosis. Iodide efflux from reconstituted proteoliposomes mediated by CFTR allows studies of channel activity and the effects of small molecules.

정제 된 야생형과 돌연변이 체 CFTR 단백질의 기능의 재구성 및 채널 활동 측정

The Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) is a unique channel-forming member of the ATP Binding Cassette (ABC) superfamily of ...

Membrane Transport Processes Analyzed by a Highly Parallel Nanopore Chip System at Single Protein Resolution

Membrane protein transport on the single protein level still evades detailed analysis, if the substrate translocated is non-electrogenic. Considerable efforts have been made in this field, but techniques enabling automated high-throughput transport analysis in combination with solvent-free lipid bilayer techniques required for the analysis of membrane transporters are rare. This class of transporters however is crucial in cell homeostasis and therefore a key target in drug development and methodologies to gain new insights desperately needed.
The here presented manuscript describes the establishment and handling of a novel biochip for the analysis of membrane protein mediated transport processes at single transporter resolution. The biochip is composed of microcavities enclosed by nanopores that is highly parallel in its design and can be produced in industrial grade and quantity. Protein-harboring liposomes can directly be applied to the chip surface forming self-assembled pore-spanning lipid bilayers using SSM-techniques (solid supported lipid membranes). Pore-spanning parts of the membrane are freestanding, providing the interface for substrate translocation into or out of the cavity space, which can be followed by multi-spectral fluorescent readout in real-time. The establishment of standard operating procedures (SOPs) allows the straightforward establishment of protein-harboring lipid bilayers on the chip surface of virtually every membrane protein that can be reconstituted functionally. The sole prerequisite is the establishment of a fluorescent read-out system for non-electrogenic transport substrates.
High-content screening applications are accomplishable by the use of automated inverted fluorescent microscopes recording multiple chips in parallel. Large data sets can be analyzed using the freely available custom-designed analysis software. Three-color multi spectral fluorescent read-out furthermore allows for unbiased data discrimination into different event classes, eliminating false positive results.
The chip technology is currently based on SiO2 surfaces, but further functionalization using gold-coated chip surfaces is also possible.

The presented protocol describes the analysis of membrane protein mediated transport on the single transporter level using pore-spanning solvent-free lipid bilayers. This is achieved by the creation of bulk produced nanopore array chips, combined with highly parallel data acquisition and analysis, enabling the future establishment of membrane protein effector screenings.

멤브레인 운송은 단일 단백질 해상도에서 고도의 병렬 나노 기공 칩 시스템에 의해 분석 처리합니다

Membrane protein transport on the single protein level still evades detailed analysis, if the substrate translocated is non-electrogenic. Considerable ...

Proteoliposome 기반 유출 분석은 CL의 단일 분자의 속성을 확인하는

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