Dynamics of the EAG1 K⁺ channel selectivity filter assessed by molecular dynamics simulations

详细信息    查看全文

• 作者：Harald Bernsteiner¹ ; Michael Brü ; ndl¹ ; Anna Stary-Weinzinger ; ^{anna.stary@univie.ac.at}
• 关键词：Molecular dynamics simulation ; KCNH1 channel ; Ion binding sites ; Y464A mutant ; Na+ binding sites ; C-type inactivation
• 刊名：Biochemical and Biophysical Research Communications
• 出版年：2017
• 出版时间：26 February 2017
• 年：2017
• 卷：484
• 期：1
• 页码：107-112
• 全文大小：1535 K
• 卷排序：484

文摘

EAG1 channels belong to the KCNH family of voltage gated potassium channels. They are expressed in several brain regions and increased expression is linked to certain cancer types. Recent cryo-EM structure determination finally revealed the structure of these channels in atomic detail, allowing computational investigations. In this study, we performed molecular dynamics simulations to investigate the ion binding sites and the dynamical behavior of the selectivity filter. Our simulations suggest that sites S2 and S4 form stable ion binding sites, while ions placed at sites S1 and S3 rapidly switched to sites S2 and S4. Further, ions tended to dissociate away from S0 within less than 20 ns, due to increased filter flexibility. This was followed by water influx from the extracellular side, leading to a widening of the filter in this region, and likely non-conductive filter configurations. Simulations with the inactivation-enhancing mutant Y464A or Na+ ions lead to trapped water molecules behind the SF, suggesting that these simulations captured early conformational changes linked to C-type inactivation.