Study of membrane protein structure by NMR spectroscopy: the KcsA channel

通过 NMR 波谱研究膜蛋白结构：KcsA 通道

• 批准号: 7734019
• 负责人: Ad - Bax
• 金额: $ 10.16万
• 依托单位: NATIONAL INSTITUTE OF DIABETES AND DIGESTIVE AND KIDNEY DISEASES
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/7734019
• 关键词: Behavior; Biological Models; Chemicals; Coupling; Data; Drug Delivery Systems; Helix (Snails); Ligand Binding; Membrane; Membrane Proteins; Micelles; Modeling; Molecular Conformation; NMR Spectroscopy; Physiological; Potassium Channel; Relaxation; Residual state; Screening procedure; Solutions; Solvents; Structure; Technology; Time; Vertebral column; base; ear helix; milligram; monomer; potassium ion; protein structure

KcsA is a homotetrameric 68-kDa membrane-associated potassium channel which selectively gates the flux of potassium ions across the membrane. The channel is known to undergo a pH-dependent open-to-closed transition. Following a study of the intact tetrameric channel, we have carried out an NMR study of the monomeric subunit of the channel (KcsAM), solubilized in SDS micelles. Chemical shift, solvent exchange, backbone 15N relaxation and residual dipolar coupling (RDC) data show the TM1 helix to remain intact, but the TM2 helix contains a distinct kink, which is subject to concentration-independent but pH-dependent conformational exchange on a microsecond time scale. The kink region, centered at G99, was previously implicated in gating of the tetrameric KcsA channel. An RDC-based model of KcsAM at acidic pH orients TM1 and the two helical segments of the kinked TM2 in a configuration reminiscent of the open conformation of the channel. Thus, the transition between states appears to be an inherent capability of the monomer, with the tetrameric assembly exerting a modulatory effect upon the transition which gives the channel its physiological gating profile.

KCSA是一种同四聚体的68 kDa膜相关钾通道，它选择性地门控膜上钾离子的通量。众所周知，该通道经历了一个依赖于pH的从开放到关闭的转变。在研究了完整的四聚体通道之后，我们对溶解在十二烷基硫酸钠胶束中的通道单体亚单位(KcsAM)进行了核磁共振研究。化学位移、溶剂交换、主干15N驰豫和剩余偶极耦合(RDC)数据表明TM1螺旋保持完整，但TM2螺旋包含一个明显的扭结，这在微秒级上受到浓度无关但pH依赖的构象交换的影响。以G99为中心的扭结区先前被认为与四聚体KCSA通道的门控有关。在酸性pH下，基于RDC的KcsAM模型将TM1和扭结的TM2的两个螺旋片段定位在一种使人想起通道开放构象的配置中。因此，状态之间的转变似乎是单体的固有能力，四聚体组装对转变施加调制效应，从而使通道具有生理门控轮廓。

项目成果

31P chemical shift anisotropy as an aid in determining nucleic acid structure in liquid crystals.

31P 化学位移各向异性有助于确定液晶中的核酸结构。

• DOI: 10.1021/ja015650x
• 发表时间: 2001
• 期刊: Journal of the American Chemical Society
• 影响因子: 15
• 作者: Wu,Z;Tjandra,N;Bax,A
• 通讯作者: Bax,A

Comparison of structure and dynamics of micelle-bound human alpha-synuclein and Parkinson disease variants.

胶束结合的人类 α-突触核蛋白和帕金森病变体的结构和动力学比较。

• DOI: 10.1074/jbc.m507624200
• 发表时间: 2005
• 期刊: The Journal of biological chemistry
• 作者: Ulmer,TobiasS;Bax,Ad
• 通讯作者: Bax,Ad

1H-1H dipolar couplings provide a unique probe of RNA backbone structure.

1H-1H 偶极耦合提供了 RNA 主链结构的独特探针。

• DOI: 10.1021/ja0388212
• 发表时间: 2003
• 期刊: Journal of the American Chemical Society
• 影响因子: 15
• 作者: Miclet,Emeric;O'Neil-Cabello,Erin;Nikonowicz,EdwardP;Live,David;Bax,Ad
• 通讯作者: Bax,Ad

2'-hydroxyl proton positions in helical RNA from simultaneously measured heteronuclear scalar couplings and NOEs.

来自同时测量的异核标量耦合和 NOE 的螺旋 RNA 中的 2-羟基质子位置。

• DOI: 10.1021/ja0606226
• 发表时间: 2006
• 期刊: Journal of the American Chemical Society
• 影响因子: 15
• 作者: Ying,Jinfa;Bax,Ad
• 通讯作者: Bax,Ad

H...N hydrogen bond lengths in double stranded DNA from internucleotide dipolar couplings.

核苷酸间偶极耦合双链 DNA 中的 H...N 氢键长度。

• DOI: 10.1023/a:1011250219293
• 发表时间: 2001
• 期刊: Journal of biomolecular NMR
• 影响因子: 2.7
• 作者: Wu,Z;Ono,A;Kainosho,M;Bax,A
• 通讯作者: Bax,A