Single-Molecule Force Spectroscopy Studies of Missense Titin Mutations That Are Likely Causing Cardiomyopathy.
Single-Molecule Force Spectroscopy Studies of Missense Titin Mutations That Are Likely Causing Cardiomyopathy.
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DOI：
10.1021/acs.langmuir.1c02006
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发表时间：
2021-10-19
期刊：
影响因子：
3.9
通讯作者：
Li, Hongbin
中科院分区：
文献类型：
--
作者：
Zuo, Jiacheng;Zhan, Denghuang;Xia, Jiahao;Li, Hongbin
巨型肌肉蛋白Titin在心脏功能中起着重要作用。肌动蛋白的突变已经成为家族性心肌病的主要原因。已经在心肌病患者中发现了错义突变；然而，区分致病突变和良性突变是具有挑战性的。鉴于肌动蛋白力学在心脏功能中的重要性，阐明在心脏肌动蛋白弹性I带部分发现的引起心肌病的突变的机械表型至关重要。利用单分子原子力显微镜(AFM)和平衡化学变性，我们研究了两个错义突变R57C-I94和S22P-I84的力学和热力学效应，生物信息学分析预测这两个错义突变位于心脏titin的弹性I带部分，可能导致心肌病。我们的AFM结果表明，突变R57C对I94模块具有显著的失稳效应。R57C使I94的机械去折叠力降低了∼30-40 pN，加速了去折叠动力学，减慢了折叠速度。这些效应共同增加了I94的展开倾向，可能导致肌动蛋白弹性的改变。相比之下，S22P仅导致I84的轻微不稳定，∼10 Pn的去折叠力降低。这种温和的不稳定不太可能导致Titin弹性的变化。这些结果将作为阐明心肌病导致弹性I带突变的机制表型的第一步。
The giant muscle protein titin plays important roles in heart function. Mutations in titin have emerged as a major cause of familial cardiomyopathy. Missense mutations have been identified in cardiomyopathy patients; however, it is challenging to distinguish disease-causing mutations from benign ones. Given the importance of titin mechanics in heart function, it is critically important to elucidate the mechano-phenotypes of cardiomyopathy-causing mutations found in the elastic I-band part of cardiac titin. Using single-molecule atomic force microscopy (AFM) and equilibrium chemical denaturation, we investigated the mechanical and thermodynamic effects of two missense mutations, R57C-I94 and S22P-I84, found in the elastic I-band part of cardiac titin that were predicted to be likely causing cardiomyopathy by bioinformatics analysis. Our AFM results showed that mutation R57C had a significant destabilization effect on the I94 module. R57C reduced the mechanical unfolding force of I94 by ∼30–40 pN, accelerated the unfolding kinetics, and decelerated the folding. These effects collectively increased the unfolding propensity of I94, likely resulting in altered titin elasticity. In comparison, S22P led to only modest destabilization of I84, with a decrease in unfolding force by ∼10 pN. It is unlikely that such a modest destabilization would lead to a change in titin elasticity. These results will serve as the first step toward elucidating mechano-phenotypes of cardiomyopathy-causing mutations in the elastic I-band.
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影响因子：
56.9
作者：
LABEIT, S;KOLMERER, B
通讯作者：
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