Allosteric-activation mechanism of BK channel gating ring triggered by calcium ions

作者：Guan, Ronghua; Zhou, Hui; Li, Junwei; Xiao, Shaoying; Pang, Chunli; Chen, Yafei; Du, Xiangrong; Ke, Shaoxi; Tang, Qiongyao; Su, Jiguo; Zhan, Yong^*; An, Hailong^*

来源：PLos One, 2017, 12(9): e0182067.

DOI：10.1371/journal.pone.0182067

• PLANAR LIPID BILAYERS
• LARGE-CONDUCTANCE
• MOLECULAR-DYNAMICS
• CA2+
• IDENTIFICATION
• QUALITY
• MUSCLE
• PRODY

Calcium ions bind at the gating ring which triggers the gating of BK channels. However, the allosteric mechanism by which Ca2+ regulates the gating of BK channels remains obscure. Here, we applied Molecular Dynamics ( MD) and Targeted MD to the integrated gating ring of BK channels, and achieved the transition from the closed state to a half-open state. Our date show that the distances of the diagonal subunits increase from 41.0 angstrom at closed state to 45.7 angstrom or 46.4 angstrom at a half-open state. It is the rotatory motion and flower-opening like motion of the gating rings which are thought to pull the bundle crossing gate to open ultimately. Compared with the 'Ca2+ bowl' at RCK2, the RCK1 Ca2+ sites make more contribution to opening the channel. The allosteric motions of the gating ring are regulated by three group of interactions. The first weakened group is thought to stabilize the close state; the second strengthened group is thought to stabilize the open state; the third group thought to lead AC region forming the CTD pore to coordinated motion, which exquisitely regulates the conformational changes during the opening of BK channels by Ca2+.

• 出版日期2017-9-27
• 单位徐州医科大学; 河北工业大学; 燕山大学; 华北电力大学（保定）; 华北电力大学