Suenaga N, Ohtsuki I
J Biochem. 1982 Apr;91(4):1249-56. doi: 10.1093/oxfordjournals.jbchem.a133809.
Effects of troponin (TN) components and tropomyosin (TM) on the interactions between actin filament and cytochalasin B (CB) at low ionic strength were investigated using electron microscopy and viscometry. CB decreased the viscosity of the actin filament and this effect became apparent at 10 microM CB and reached the maximum at 40 microM. CB (40 microM) shortened the average actin filament length from 0.50 to 0.25 micrometers as observed electron microscopically. Presence of TN components and TM diminished the effect of CB on both viscosity and filament length. TN-T but not TN-I had an inhibitory effect on the decrease of the viscosity of the A+TM filament induced by CB. TN-T1 but not TN-T2, one of two chymotryptic subfragments of TN-T, had the same inhibitory effect seen with TN-T. Thus, the cooperation between the T1 region of TN-T and TM is probably essential for the inhibitory action on CB-actin interactions.
利用电子显微镜和粘度测定法，研究了肌钙蛋白（TN）成分和原肌球蛋白（TM）在低离子强度下对肌动蛋白丝与细胞松弛素B（CB）之间相互作用的影响。CB降低了肌动蛋白丝的粘度，这种效应在10微摩尔CB时变得明显，并在40微摩尔时达到最大值。如电子显微镜观察到的，40微摩尔的CB将肌动蛋白丝的平均长度从0.50微米缩短至0.25微米。TN成分和TM的存在减弱了CB对粘度和丝长度的影响。TN-T而非TN-I对CB诱导的A+TM丝粘度降低具有抑制作用。TN-T的两个胰凝乳蛋白酶亚片段之一TN-T1而非TN-T2具有与TN-T相同的抑制作用。因此，TN-T的T1区域与TM之间的协同作用可能对抑制CB-肌动蛋白相互作用至关重要。
