通过对嵌合轮藻肌球蛋白的研究揭示了转换器区域对肌球蛋白运动性的重要性。

Importance of the converter region for the motility of myosin as revealed by the studies on chimeric Chara myosins.

作者信息

Seki Masaya, Kashiyama Taku, Hachikubo You, Ito Kohji, Yamamoto Keiichi

机构信息

Department of Biology, Chiba University, Inage-ku, 263-8522 Chiba, Japan.

出版信息

J Mol Biol. 2004 Nov 19;344(2):311-5. doi: 10.1016/j.jmb.2004.09.039.

DOI:10.1016/j.jmb.2004.09.039

PMID:15522286

Abstract

A long alpha-helix in myosin head constitutes a lever arm together with light chains. It is known from X-ray crystallographic studies that the first three turns of this lever arm alpha-helix are inserted into the converter region of myosin. We previously showed that chimeric Chara myosin in which the motor domain of Chara myosin was connected to the lever arm alpha-helix of Dictyostelium myosin had motility far less than that expected for the motor domain of Chara myosin. Here, we replaced the inserted three turns of alpha-helix of Dictyostelium myosin with that of the Chara myosin and found that the replacement enhanced the motility 2.6-fold without changing the ATPase activity so much. The result clearly showed the importance of interaction between the converter region and the lever arm alpha-helix for the efficient motility of myosin.

摘要

肌球蛋白头部的一个长α螺旋与轻链共同构成一个杠杆臂。从X射线晶体学研究可知，这个杠杆臂α螺旋的前三圈插入到肌球蛋白的转换器区域。我们之前表明，将衣藻肌球蛋白的马达结构域连接到盘基网柄菌肌球蛋白的杠杆臂α螺旋上的嵌合衣藻肌球蛋白，其运动能力远低于衣藻肌球蛋白马达结构域预期的运动能力。在这里，我们用衣藻肌球蛋白的α螺旋取代了盘基网柄菌肌球蛋白插入的三圈α螺旋，发现这种取代使运动能力提高了2.6倍，而ATP酶活性没有太大变化。结果清楚地表明了转换器区域与杠杆臂α螺旋之间的相互作用对肌球蛋白高效运动的重要性。