Binding of calcium and magnesium to myosin in skeletal muscle myofibrils.
Binding of calcium and magnesium to myosin in skeletal muscle myofibrils.
复制标题
钙和镁与骨骼肌肌原纤维中的肌球蛋白结合。
作者：
J. Borejdo;M. Werber
二价阳离子与肌球蛋白的结合曲线已经在肌原纤维中获得，其中肌球蛋白以典型的体内组织的阵列组装。保护由Ca 2+和Mg 2+离子的区域的肌球蛋白对胰凝乳蛋白酶攻击敏感提供了监测金属离子结合的手段。二价阳离子的各种浓度的糜蛋白酶消化模式的效果进行了评估，通过光密度测定的考马斯亮蓝染色的凝胶获得的聚丙烯酰胺凝胶电泳在十二烷基硫酸钠的存在下，肌原纤维溶解的速率。结果表明存在两类亲和力相差4个数量级的结合位点。与肌球蛋白的5，5 '-二硫代双（2-硝基苯甲酸）可解离轻链相关的高亲和力位点的饱和度调节肌球蛋白亚片段1的产生。从作为金属离子浓度的函数的消化曲线，获得Mg 2+和Ca 2+的结合常数。Mg 2+的值为5.7 x 10（6）M-1，比溶液中游离肌球蛋白的最新测定值高约1个数量级; Ca 2+的值为6.3 x 10（6）M-1。与低亲和力位点的结合调节了重酶解肌球蛋白片段的产生，并产生了Ca 2+和Mg 2+的缔合常数，分别为0.9 x 10（3）和0.7 x 10（3）M-1。
Binding profiles for divalent cation to myosin have been obtained in myofibrils where myosin is assembled in arrays typical of the in vivo organization. Protection by Ca2+ and Mg2+ ions of the regions of myosin susceptible to chymotryptic attack provided the means to monitor metal ion binding. The effect of various concentrations of divalent cations on the chymotryptic digestion patterns was assessed by densitometry of Coomassie Blue stained gels obtained by polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate and by the rate of myofibrillar solubilization. The results indicate the presence of two classes of binding sites differing in affinity by 4 orders of magnitude. The fractional saturation of the high-affinity site associated with the 5,5'-dithiobis(2-nitrobenzoic acid)-dissociable light chains of myosin regulated the production of subfragment 1 of myosin. From the digestion profiles as a function of metal ion concentration, binding constants for Mg2+ and Ca2+ were obtained. The value for Mg2+ was 5.7 x 10(6) M-1, which is about 1 order of magnitude higher than the most recently determined values for free myosin in solution; the value for Ca2+ was 6.3 x 10(6) M-1. Binding to the low-affinity site regulated the production of the heavy meromyosin fragment and yielded association constants for Ca2+ and Mg2+ of 0.9 x 10(3) and 0.7 x 10(3) M-1, respectively.
影响因子：
2.9
作者：
S. Oda;C. Oriol-Audit;E. Reisler
通讯作者：
S. Oda;C. Oriol-Audit;E. Reisler
骨骼肌中的跨桥运动和肌球蛋白铰链的构象状态。
影响因子：
5.6
作者：
Ueno,H;Harrington,WF
通讯作者：
Harrington,WF