Mrakovcić-Zenic A, Reisler E
Biochemistry. 1983 Feb 1;22(3):525-30. doi: 10.1021/bi00272a001.
The effect of phosphorylation of the myosin light chains (LC-2) on cross-bridge conformation in synthetic myosin filaments from vertebrate skeletal muscle was studied by using chemical cross-linking and chymotryptic digestion methods. Phosphorylated and dephosphorylated myosin filaments, which were used in these experiments, had similar sedimentation coefficients, turbidities, and rates of growth from the respective minifilament structures. The proteolytic susceptibility at the heavy meromyosin-light meromyosin (HMM-LMM) junction was somewhat greater in the phosphorylated than in the dephosphorylated filaments at both pH 7.0 and pH 8.0. At the same time, the normalized rate of subfragment 2 (S-2) cross-linking to the filament surface, kS-2/kLMM, was reduced by phosphorylation of myosin. These results are consistent with partial release of cross-bridges from the thick filament surface in phosphorylated myosin filaments.
通过化学交联和胰凝乳蛋白酶消化方法，研究了脊椎动物骨骼肌合成肌球蛋白丝中肌球蛋白轻链（LC-2）磷酸化对横桥构象的影响。这些实验中使用的磷酸化和去磷酸化肌球蛋白丝，具有相似的沉降系数、浊度以及从各自的微丝结构生长的速率。在pH 7.0和pH 8.0时，磷酸化丝在重酶解肌球蛋白-轻酶解肌球蛋白（HMM-LMM）连接处的蛋白水解敏感性比去磷酸化丝略高。同时，肌球蛋白磷酸化使亚片段2（S-2）与丝表面交联的标准化速率kS-2/kLMM降低。这些结果与磷酸化肌球蛋白丝中横桥从粗丝表面部分释放相一致。
