Conformational transition in the myosin hinge upon activation of muscle.
Conformational transition in the myosin hinge upon activation of muscle.
复制标题
肌球蛋白的构象转变取决于肌肉的激活。
DOI：
10.1073/pnas.78.10.6101
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发表时间：
1981
影响因子：
11.1
通讯作者：
Harrington,WF
中科院分区：
文献类型：
--
作者：
Ueno,H;Harrington,WF
我们已经确定了速率糜蛋白酶蛋白水解的肌球蛋白铰链区在甘油兔腰肌纤维和肌原纤维在僵硬诱导，激活和放松缓冲液。轻酶解肌球蛋白（LMM）形成的时间过程为铰链结构域内的切割提供了特异性探针。在僵硬诱导和放松缓冲液中，铰链内的蛋白水解被抑制，但在激活时，LMM以显著增加的速率形成，这取决于MgATP的浓度。肽键裂解发生在跨越铰链结构域长度的四个广泛分离的位点处。只有少量的蛋白水解发生在头部-杆旋转或头部本身的重链（S-1亚基）在严谨的诱导和放松溶剂，我们没有发现显着的变化激活。通过加入MgADP、Pi或腺苷5 ′-[β，γ-亚氨基]三磷酸镁或在活化溶剂中在粗丝和细丝之间的零重叠下，在僵直诱导缓冲液中LMM的形成速率不变。这些结果为骨骼肌激活后肌球蛋白铰链内的构象（螺旋-卷曲）转变提供了证据。
We have determined the rates of chymotryptic proteolysis of the myosin hinge region in glycerinated rabbit psoas fibers and myofibrils in in rigor-inducing, activating, and relaxing buffers. The time course of formation of light meromyosin (LMM) provides a specific probe for cleavage within the hinge domain. In rigor-inducing and relaxing buffers proteolysis within the hinge is depressed, but on activation LMM is formed at a markedly increased rate, which is dependent on the concentration of MgATP. Peptide bond cleavage occurs at four widely separated sites spanning the length of the hinge domain. Only a trivial amount of proteolysis occurs at the head--rod swivel or within the heavy chain of the head itself (S-1 subunit) in rigor-inducing and relaxing solvents, and we find no significant change on activation. The rate of formation of LMM in rigor-inducing buffer is unchanged by addition of MgADP, Pi, or magnesium adenosine 5'-[beta, gamma-imido]triphosphate or in activating solvent at zero overlap between thick and thin filaments. These results provide evidence for a conformational (helix--coil) transition within the myosin hinge upon activation of skeletal muscle.