Metal cation controls myosin and actomyosin kinetics.
Metal cation controls myosin and actomyosin kinetics.
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金属阳离子控制肌球蛋白和肌动球蛋白动力学。
DOI：
10.1002/pro.2376
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发表时间：
2013
期刊：
影响因子：
--
通讯作者：
Nesmelov,YuriE
中科院分区：
文献类型：
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作者：
Tkachev,YaroslavV;Ge,Jinghua;Negrashov,IgorV;Nesmelov,YuriE
我们用镁、锰或钙核苷酸复合物干扰肌球蛋白核苷酸结合位点，用金属阳离子作为探针，研究肌动蛋白存在下肌球蛋白ATP酶的途径。我们使用了瞬时时间分辨FRET、肌球蛋白内源荧光、芘标记肌动蛋白的荧光，结合先前表征的盘状果蝇肌球蛋白构建体A639C：K498C的稳态肌球蛋白ATP酶活性测量。我们发现，肌动蛋白激活肌球蛋白ATP酶不依赖于金属阳离子，无论核苷酸结合和解离的阳离子特异性动力学。肌球蛋白ATP酶的限速步骤取决于金属阳离子。恢复冲程和反向恢复冲程的速率与阳离子的离子半径成正比。从肌球蛋白和肌动球蛋白释放核苷酸的速率以及ATP与肌动球蛋白的结合取决于阳离子配位数。
We have perturbed myosin nucleotide binding site with magnesium‐, manganese‐, or calcium‐nucleotide complexes, using metal cation as a probe to examine the pathways of myosin ATPase in the presence of actin. We have used transient time‐resolved FRET, myosin intrinsic fluorescence, fluorescence of pyrene labeled actin, combined with the steady state myosin ATPase activity measurements of previously characterizedD.discoideummyosin construct A639C:K498C. We found that actin activation of myosin ATPase does not depend on metal cation, regardless of the cation‐specific kinetics of nucleotide binding and dissociation. The rate limiting step of myosin ATPase depends on the metal cation. The rate of the recovery stroke and the reverse recovery stroke is directly proportional to the ionic radius of the cation. The rate of nucleotide release from myosin and actomyosin, and ATP binding to actomyosin depends on the cation coordination number.