The Local Environment of Loop Switch 1 Modulates the Rate of ATP-Induced Dissociation of Human Cardiac Actomyosin.
The Local Environment of Loop Switch 1 Modulates the Rate of ATP-Induced Dissociation of Human Cardiac Actomyosin.
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DOI：
10.3390/ijms23031220
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发表时间：
2022-01-22
影响因子：
5.6
通讯作者：
Nesmelov YE
中科院分区：
文献类型：
--
作者：
Gargey A;Nesmelov YE
人心肌肌球蛋白的两种亚型α和β具有显著的序列相似性，但表现出不同的动力学。α亚型是一个更快的马达;在肌动球蛋白循环中，它花更少的时间与肌动蛋白强烈结合。对于α亚型，肌动球蛋白在ATP结合时解离得更快，ADP对肌动球蛋白的亲和力较弱。可以认为，异构体特异性肌动球蛋白的动力学调节在人心肌肌球蛋白的核苷酸结合位点。肌球蛋白是一种P-环ATP酶;核苷酸结合位点由P-环和环开关1和2组成。所有三个环定位MgATP以成功水解。环序列是保守的两种肌球蛋白亚型，我们推测，活性位点附近的亚型特异性结构元件调节核苷酸结合和释放的速率。之前，我们进行了分子动力学模拟，发现环开关1附近的环S291-E317更紧凑，并且在β亚型中的氨基酸残基位置比在α亚型中的氨基酸残基位置具有更大的波动。在α亚型中，环与环开关1形成盐桥，该桥不存在于β亚型中。环S291-E317的两个异亮氨酸I303和I313被α同种型的缬氨酸替换。我们在β亚型背景中引入了一个双突变I303 V：I313 V，并研究了该突变如何影响肌动球蛋白的ATP结合率和ADP解离率。我们发现，ATP诱导的肌动球蛋白解离发生更快的突变体，但ADP的释放率仍然是相同的野生型β亚型。由于环S291-E317和环开关1的接近，ATP诱导的肌动球蛋白解离的更快速率表明环S291-E317影响环开关1的结构动力学，并且环开关1控制ATP与活性位点的结合。在突变体和野生型肌球蛋白构建体中ADP从肌动球蛋白解离的相似速率表明环开关1不控制ADP从肌动球蛋白释放。
Two isoforms of human cardiac myosin, alpha and beta, share significant sequence similarities but show different kinetics. The alpha isoform is a faster motor; it spends less time being strongly bound to actin during the actomyosin cycle. With alpha isoform, actomyosin dissociates faster upon ATP binding, and the affinity of ADP to actomyosin is weaker. One can suggest that the isoform-specific actomyosin kinetics is regulated at the nucleotide binding site of human cardiac myosin. Myosin is a P-loop ATPase; the nucleotide-binding site consists of P-loop and loops switch 1 and 2. All three loops position MgATP for successful hydrolysis. Loops sequence is conserved in both myosin isoforms, and we hypothesize that the isoform-specific structural element near the active site regulates the rate of nucleotide binding and release. Previously we ran molecular dynamics simulations and found that loop S291-E317 near loop switch 1 is more compact and exhibits larger fluctuations of the position of amino acid residues in beta isoform than in alpha. In alpha isoform, the loop forms a salt bridge with loop switch 1, the bridge is not present in beta isoform. Two isoleucines I303 and I313 of loop S291-E317 are replaced with valines in alpha isoform. We introduced a double mutation I303V:I313V in beta isoform background and studied how the mutation affects the rate of ATP binding and ADP dissociation from actomyosin. We found that ATP-induced actomyosin dissociation occurs faster in the mutant, but the rate of ADP release remains the same as in the wild-type beta isoform. Due to the proximity of loop S291-E317 and loop switch 1, a faster rate of ATP-induced actomyosin dissociation indicates that loop S291-E317 affects structural dynamics of loop switch 1, and that loop switch 1 controls ATP binding to the active site. A similar rate of ADP dissociation from actomyosin in the mutant and wild-type myosin constructs indicates that loop switch 1 does not control ADP release from actomyosin.
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影响因子：
2.7
作者：
Gargey A;Iragavarapu SB;Grdzelishvili AV;Nesmelov YE
通讯作者：
Nesmelov YE
DOI：
10.1016/j.bbrc.2019.01.045
发表时间：
2019-02-19
影响因子：
3.1
作者：
Gargey, Akhil;Ge, Jinghua;Nesmelov, Yuri E.
通讯作者：
Nesmelov, Yuri E.
影响因子：
4.8
作者：
WALLER, GS;OUYANG, G;LOWEY, S
通讯作者：
LOWEY, S
DOI：
10.1002/cm.21650
发表时间：
2021-01
期刊：
Cytoskeleton (Hoboken, N.J.)
影响因子：
--
作者：
Walker BC;Walczak CE;Cochran JC
通讯作者：
Cochran JC
影响因子：
2.9
作者：
Shimada, T;Sasaki, N;Sutoh, K
通讯作者：
Sutoh, K