Mutational Insight into Allosteric Regulation of Kir Channel Activity.
Mutational Insight into Allosteric Regulation of Kir Channel Activity.
复制标题
DOI：
10.1021/acsomega.2c04456
复制
发表时间：
2022-12-06
期刊：
影响因子：
4.1
通讯作者：
Wylie, Benjamin J.
中科院分区：
文献类型：
--
作者：
Yekefallah, Maryam;Rasberry, Carver A.;Aalst, Evan J. Van;Browning, Holley P.;Amani, Reza;Versteeg, Derek B.;Wylie, Benjamin J.
钾离子通道在一定程度上受螺旋束交叉（或称内通道）和选择性过滤器（或称外通道）之间的变构通信调节。这个网络是由门控刺激触发的。同时，还有一个变构网络，它是一组共轭的相互作用，这些相互作用与通道功能所需的远程结构重排有关。向内整流K+ (Kir)通道有利于向内K+电导，是配体门控的，并有助于建立静息膜电位。KirBac1.1是一种与人类Kir （hKir）通道同源的细菌Kir （KirBac）通道。此外，KirBac1.1被阴离子磷脂配体磷脂酰甘油（PG）门控。在这项研究中，我们使用位点定向诱变来研究KirBac1.1门控机制和变构网络中涉及的残基，我们之前使用详细的固态核磁共振（SSNMR）测量。使用基于荧光的K+和钠（Na+）通量测定，我们确定了功能受损但不改变通道选择性的通道突变体。同时，我们进行了粗粒分子动力学模拟，观察了PG-KirBac1.1相互作用与突变通道活性的变化，以及与这种行为相关的两个跨膜螺旋和孔螺旋之间的接触。脂质亲和性与邻近亚基上两个色氨酸残基的接近性密切相关，这些亚基将阴离子脂质吸引到由一簇精氨酸残基形成的阳离子口袋中。因此，这些模拟为每个突变位点在拟议的变构网络中的作用建立了结构和功能基础。实验和模拟数据提供了对参与门控和K+通道脂质变构的关键功能残基的深入了解。我们的发现也对hKir通道的生理学有直接的影响，因为我们在KirBac1.1中发现的许多残基都是守恒的。
Potassium (K+) channels are regulated in part by allosteric communication between the helical bundle crossing, or inner gate, and the selectivity filter, or outer gate. This network is triggered by gating stimuli. In concert, there is an allosteric network which is a conjugated set of interactions which correlate long-range structural rearrangements necessary for channel function. Inward-rectifier K+ (Kir) channels favor inward K+ conductance, are ligand-gated, and help establish resting membrane potentials. KirBac1.1 is a bacterial Kir (KirBac) channel homologous to human Kir (hKir) channels. Additionally, KirBac1.1 is gated by the anionic phospholipid ligand phosphatidylglycerol (PG). In this study, we use site-directed mutagenesis to investigate residues involved in the KirBac1.1 gating mechanism and allosteric network we previously proposed using detailed solid-state NMR (SSNMR) measurements. Using fluorescence-based K+ and sodium (Na+) flux assays, we identified channel mutants with impaired function that do not alter selectivity of the channel. In tandem, we performed coarse grain molecular dynamics simulations, observing changes in PG-KirBac1.1 interactions correlated with mutant channel activity and contacts between the two transmembrane helices and pore helix tied to this behavior. Lipid affinity is closely tied to the proximity of two tryptophan residues on neighboring subunits which lure anionic lipids to a cationic pocket formed by a cluster of arginine residues. Thus, these simulations establish a structural and functional basis for the role of each mutated site in the proposed allosteric network. The experimental and simulated data provide insight into key functional residues involved in gating and lipid allostery of K+ channels. Our findings also have direct implications on the physiology of hKir channels due to conservation of many of the residues identified in this work from KirBac1.1.
登录
查看更多内容
影响因子：
5.3
作者：
Djukic, Biljana;Casper, Kristen B.;McCarthy, Ken D.
通讯作者：
McCarthy, Ken D.
KirBac1.1 突变体的分子动力学模拟揭示了 Kir 通道的全局门控变化。
影响因子：
5.6
作者：
Linder, Tobias;Wang, Shizhen;Zangerl-Plessl, Eva-Maria;Nichols, Colin G.;Stary-Weinzinger, Anna
通讯作者：
Stary-Weinzinger, Anna
影响因子：
5.5
作者：
Hager NA;McAtee CK;Lesko MA;O'Donnell AF
通讯作者：
O'Donnell AF
影响因子：
6.8
作者：
Cordero-Morales JF;Vásquez V
通讯作者：
Vásquez V
影响因子：
5.6
作者：
Khan, Abbas;Zia, Tauqir;Wei, Dong-Qing
通讯作者：
Wei, Dong-Qing