Analysis of mechanical properties of mutant myosin linked to nonsyndromic hereditary deafness, DFNA17

与非综合征性遗传性耳聋相关的突变肌球蛋白的机械特性分析，DFNA17

• 批准号: 18590210
• 负责人: CHAEN Shigeru
• 金额: $ 2.44万
• 依托单位: Nihon University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 2006
• 资助国家: 日本
• 起止时间: 2006 至 2007
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-18590210/
• 关键词: nonsyndrmnic hereditary deafness; myosin; genetic engineenng; fulorescence enemy tranfer; activation ener; optical trap; 遣伝性難聴; アクチン; In Vitro Motility Assay; ATP分解活性; 蛍光エネルギー移動

A replacement of conserved arginine in the SH1 helix with histidine is revealed to be linked to nonsyndromic hereditary deafness, DFNA17. To investigate the involvement of the SH1 helix in mechanical properties of myosin, we have introduced a point mutation into the SH1 helix of Dictyosterium myosin II The mutation resulted in a significant impairment in motile activities, while actin-activated ATPase activity was only slightly affected. Single molecule mechanical measurements using optical trap showed that step size was not shortened, suggesting that the slower motility is caused by altered kinetics. The single molecule measurements demonstrated that the mutation significantly reduced cross-bridge stiffness. Motile activities produced by mixtures of wild-type ant mutant myosins also suggested that the mutation affected the elstiity of myosin. A GFP-based fluorescence resonance energy transfer study showed that the activation energy required for conformational transition was significantly reduced by the mutation. The mutation was also shown to reduce thermal stability and induce thermal aggregation of the protein, which might be implicated in the disease process.

一个保守的精氨酸在SH1螺旋与组氨酸的替代被揭示与非综合征遗传性耳聋，DFNA 17。为了研究肌球蛋白的SH 1螺旋在机械性质中的作用，我们将一个点突变引入网壳藻肌球蛋白II的SH 1螺旋中。该突变导致运动活性的显著损害，而肌动蛋白激活的ATP酶活性仅受到轻微影响。使用光学陷阱的单分子机械测量显示步长没有缩短，这表明较慢的运动性是由动力学改变引起的。单分子测量表明，突变显着降低跨桥刚度。由野生型突变肌球蛋白的混合物产生的运动活动也表明突变影响肌球蛋白的弹性。基于GFP的荧光共振能量转移研究表明，突变显著降低了构象转变所需的活化能。该突变还显示降低热稳定性并诱导蛋白质的热聚集，这可能与疾病过程有关。

项目成果

Mutation in the SH1 helix reduces the activation energy of the ATP-induced conformational transition of myosin.

SH1 螺旋的突变降低了 ATP 诱导的肌球蛋白构象转变的活化能。

• DOI: 10.1016/j.bbrc.2007.03.155
• 发表时间: 2007
• 期刊: Biochemical and biophysical research communications
• 影响因子: 3.1
• 作者: S. Iwai;S. Chaen
• 通讯作者: S. Chaen

「研究成果報告書概要(和文)」より

摘自《研究结果报告摘要（日文）》

• 发表时间: 2005
• 作者: Kawauchi;et. al.;Nishimura et al.;Dezawa et al.;Yoshizawa et al.;星野 幹雄;星野 幹雄
• 通讯作者: 星野 幹雄

A point mutation in the SH1 helix alters elasticity and thermal stability of myosin II

• DOI: 10.1074/jbc.m605365200
• 发表时间: 2006-10-13
• 期刊: JOURNAL OF BIOLOGICAL CHEMISTRY
• 影响因子: 4.8
• 作者: Iwai, Sosuke;Hanamoto, Daisuke;Chaen, Shigeru
• 通讯作者: Chaen, Shigeru