New mechanisms of action of human calcium ATPase SERCA2b revealed by cryo-EM analysis

冷冻电镜分析揭示人钙 ATP 酶 SERCA2b 的新作用机制

• 批准号: 21K15036
• 负责人: 張 玉霞
• 金额: $ 2.91万
• 依托单位: Tohoku University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Early-Career Scientists
• 财政年份: 2021
• 资助国家: 日本
• 起止时间: 2021-04-01 至 2022-03-31
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-21K15036/
• 关键词: cryo-EM; SERCA2b; Calcium pump

We newly determined several cryo-EM structures of SERCA2b, including a high-energy E1P state with two bound Ca ions and the post-E1P state immediately after Ca release. The dataset in E2P state identified a new conformation that differs from the conventional E2P state and the subsequent E2-Pi state that can be regarded as a late-stage Ca-unbound intermediate. The cryo-EM structures suggested that SERCA2b adopts multiple conformations in reaction and generates preformed states closely resembling the next intermediate. These findings provide essential structural insight into how enzymes work; multiple sub-states, including one highly similar to a next intermediate, are formed in a reaction intermediate to facilitate the transition step and thereby drive the catalytic cycle efficiently.

我们新确定了 SERCA2b 的几种冷冻电镜结构，包括具有两个结合 Ca 离子的高能 E1P 状态以及 Ca 释放后立即的 E1P 后状态。 E2P状态的数据集确定了一种不同于传统E2P状态和随后的E2-Pi状态的新构象，可以被视为后期Ca未结合中间体。冷冻电镜结构表明 SERCA2b 在反应中采用多种构象，并生成与下一个中间体非常相似的预形成状态。这些发现为酶的工作原理提供了重要的结构见解；在反应中间体中形成多种子状态，包括与下一中间体高度相似的子状态，以促进过渡步骤，从而有效地驱动催化循环。

项目成果

Cryo‐EM analysis provides new mechanistic insight into ATP binding to Ca2+‐ATPase SERCA2b

• DOI: 10.15252/embj.2021108482
• 发表时间: 2021-08
• 期刊: The EMBO Journal
• 作者: Yuxia Zhang;Satoshi Watanabe;A. Tsutsumi;H. Kadokura;M. Kikkawa;K. Inaba