肌动蛋白在ATP水解循环不同中间状态下的取向与运动性。

Orientation and mobility of actin in different intermediate states of the ATP hydrolysis cycle.

作者信息

Khaimina S S, Wrzosek A, Dabrowska R, Borovikov Yu S

机构信息

Institute of Cytology, Russian Academy of Sciences, St. Petersburg, 194064, Russia.

出版信息

Biochemistry (Mosc). 2005 Oct;70(10):1136-9. doi: 10.1007/s10541-005-0236-7.

DOI:10.1007/s10541-005-0236-7

PMID:16271030

Abstract

Using polarization fluorimetry, we have investigated conformational changes of FITC-phalloidin-labeled F-actin in ghost muscle fibers. These changes were induced by myosin subfragment-1 (S1) in the absence and presence of MgADP, MgAMP-PNP, MgATPgammaS, or MgATP. Modeling of various intermediate states was accompanied by discrete changes in actomyosin orientation and mobility of fluorescent dye dipoles. This suggests multistep changes of orientation and mobility of actin monomers during the ATPase cycle. The most pronounced differences in orientation (~~4 degrees ) and in mobility (~~43%) of actin were found between the actomyosin states induced by MgADP and MgATP.

摘要

利用偏振荧光法，我们研究了鬼肌纤维中异硫氰酸荧光素 - 鬼笔环肽标记的F - 肌动蛋白的构象变化。这些变化是在有无MgADP、MgAMP - PNP、MgATPγS或MgATP的情况下由肌球蛋白亚片段 - 1（S1）诱导产生的。各种中间状态的建模伴随着肌动球蛋白取向和荧光染料偶极子迁移率的离散变化。这表明在ATP酶循环过程中肌动蛋白单体的取向和迁移率发生了多步变化。在由MgADP和MgATP诱导的肌动球蛋白状态之间，发现肌动蛋白在取向（约4度）和迁移率（约43%）方面存在最显著的差异。