Department of Chemistry , East Carolina University , Greenville , North Carolina 27858 , United States.
J Phys Chem B. 2019 Dec 5;123(48):10163-10170. doi: 10.1021/acs.jpcb.9b08120. Epub 2019 Nov 21.
Mapping the conformational pathway of biomolecules is a great challenge because of the large size and complexity of biomolecules. The nudged elastic band (NEB) method has been applied to study the reaction pathways for both small organic molecules and small peptides of a few amino acids. In this work, for the first time, the NEB method was employed to study the conformational pathways of Annexin A1, a membrane-binding protein of 334 amino acids. The N-terminal domain conformational change from the buried state within the core domain to the exposed state outside the core domain is a vital step for Annexin A1 to interact with membranes or target proteins. In this work, multiple molecular dynamics simulations using the NEB method were performed to simulate the N-terminal domain conformational pathway of Annexin A1. Our results suggested that the N-terminal domain of Annexin A1 is removed from the repeat III of the core domain in a sliding motion. The loop region of repeat III covering the N-terminal helix in the buried state does not lift up for the N-terminal to swing out of the pocket; instead, the N-terminal pulls out from the bottom of the core domain. The N-terminal domain linker region (S27-N42) flexibility is critical for the N-terminal domain conformational changes. Our results also suggested a two-step folding process for the helix D in repeat III, M247-V250 folds first followed by the folding of L251-E254. The results demonstrated that the NEB method could be an effective tool for theoretical studies on conformational pathways of biomolecules.
对生物大分子构象途径进行映射是一项巨大的挑战,因为生物大分子的尺寸和复杂度都很大。受纳弹性带(NEB)方法已被应用于研究小分子和少数几种氨基酸组成的小肽的反应途径。在这项工作中,首次将 NEB 方法应用于研究膜结合蛋白 Annexin A1 的构象途径,该蛋白由 334 个氨基酸组成。N 端结构域从核心结构域内的埋藏状态到核心结构域外的暴露状态的构象变化是 Annexin A1 与膜或靶蛋白相互作用的关键步骤。在这项工作中,使用 NEB 方法进行了多次分子动力学模拟,以模拟 Annexin A1 的 N 端结构域构象途径。我们的结果表明,Annexin A1 的 N 端结构域以滑动运动的方式从核心结构域的重复 III 中脱离。在埋藏状态下覆盖 N 端螺旋的重复 III 的环区不会向上抬起以使 N 端从口袋中摆动出来;相反,N 端从核心结构域的底部拔出。N 端结构域连接区(S27-N42)的灵活性对 N 端结构域构象变化至关重要。我们的结果还表明,重复 III 中的螺旋 D 存在两步折叠过程,M247-V250 首先折叠,然后 L251-E254 折叠。结果表明,NEB 方法可以成为研究生物大分子构象途径的有效理论工具。
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