Investigating the inter-subunit/subdomain interactions and motions relevant to disease mutations in the N-terminal domain of ryanodine receptors by molecular dynamics simulation
Investigating the inter-subunit/subdomain interactions and motions relevant to disease mutations in the N-terminal domain of ryanodine receptors by molecular dynamics simulation
复制标题
通过分子动力学模拟研究与兰尼碱受体 N 末端结构域疾病突变相关的亚基/子域间相互作用和运动
DOI：
10.1002/prot.25318
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发表时间：
2017-09-01
影响因子：
2.9
通讯作者：
Liu, Zheng
中科院分区：
文献类型：
--
作者：
Zheng, Wenjun;Liu, Zheng
兰尼碱受体（RyR）对于横纹肌中的钙信号传导是必需的，并且已经在两种RyR同种型（骨骼肌中的RyRl和心肌中的RyR 2）中鉴定了许多疾病突变。RyRs的激活/调节机制的深入理解一直受到阻碍的高分辨率结构和动态信息的短缺，这个巨大的四聚体复合物在不同的功能状态。为了阐明RyRs疾病突变的分子机制，我们对RyRs的N-末端结构域（NTD）进行了分子动力学模拟。NTD是RyRs结构域中分辨率最高的结构部分，也是疾病突变的热点。首先，我们模拟了野生型RyR 1和三种疾病突变体（K155 E，R157 Q和R164 Q）的四聚体NTD，这些突变体干扰了亚基间的界面。我们的模拟确定了一个动态的盐桥网络，涉及在亚基/亚结构域之间的接口和疾病突变位点的带电残基。通过扰动这个关键网络，上述三个突变导致R157 Q具有最高亚基间开放概率的更大灵活性。接下来，我们在存在或不存在中心Cl-阴离子的情况下模拟了RyR 2的单体NTD，所述中心Cl-阴离子已知稳定三个NTD子域（A、B和C）之间的界面。我们发现，Cl-的损失重构的盐桥网络附近的Cl-结合位点，导致旋转的子域A/B相对于子域C和增强的流动性之间的子域。这一发现支持RyR 2的NTD中的疾病突变通过干扰Cl-结合的机制。从这项研究中获得的丰富的结构和动力学信息将指导未来的突变和功能的NTD的RyRs的研究。(C)2017 Wiley Periodicals，Inc.
The ryanodine receptors (RyR) are essential to calcium signaling in striated muscles, and numerous disease mutations have been identified in two RyR isoforms, RyRl in skeletal muscle and RyR2 in cardiac muscle. A deep understanding of the activation/ regulation mechanisms of RyRs has been hampered by the shortage of high-resolution structures and dynamic information for this giant tetrameric complex in different functional states. Toward elucidating the molecular mechanisms of disease mutations in RyRs, we performed molecular dynamics simulation of the N-terminal domain (NTD) which is not only the best-resolved structural component of RyRs, but also a hotspot of disease mutations. First, we simulated the tetrameric NTD of wild-type RyR1 and three disease mutants (K155E, R157Q, and R164Q) that perturb the inter-subunit interfaces. Our simulations identified a dynamic network of salt bridges involving charged residues at the inter-subunit/subdomain interfaces and disease-mutation sites. By perturbing this key network, the above three mutations result in greater flexibility with the highest inter-subunit opening probability for R157Q. Next, we simulated the monomeric NTD of RyR2 in the presence or absence of a central Cl- anion which is known to stabilize the interfaces between the three NTD subdomains (A, B, and C). We found that the loss of Cl- restructures the salt-bridge network near the Cl--binding site, leading to rotations of subdomain A/B relative to subdomain C and enhanced mobility between the subdomains. This finding supports a mechanism for disease mutations in the NTD of RyR2 via perturbation of the Cl- binding. The rich structural and dynamic information gained from this study will guide future mutational and functional studies of the NTD of RyRs. (C) 2017 Wiley Periodicals, Inc.