Wall substructure of microtubules polymerized in vitro from tubulin of crayfish nerve cord and fixed with tannic acid.
Wall substructure of microtubules polymerized in vitro from tubulin of crayfish nerve cord and fixed with tannic acid.
复制标题
微管的壁亚结构由小龙虾神经索的微管蛋白在体外聚合而成，并用单宁酸固定。
作者：
G. Pierson;P. Burton;R. Himes
螯虾神经索轴突的微管通常有12个壁原丝，周围神经胶质细胞的微管有13个壁原丝。从这样的神经索中分离出微管蛋白并在体外聚合;沉淀的微管的单宁酸染色显示存在具有12和13个壁原丝的微管，这表明形成具有给定数目的原丝的微管的能力是微管蛋白或其相关蛋白质所固有的。发现聚合温度影响所得微管中原丝的数量。例如，在20摄氏度下组装，大多数完整的微管有13个原丝，而在40摄氏度下，大多数微管显示10个原丝。有人建议，在体外聚合的温度，除其他因素外，可以影响相邻的原丝之间的结合角，从而改变所需的原丝的数量，以完成圆周的小管。
Microtubules of axons of crayfish nerve cord normally have 12 wall protofilaments and microtubules of surrounding glial cells have 13 protofilaments. Tubulin was isolated from such nerve cords and polymerized in vitro; tannic acid staining of sedimented microtubules showed that microtubules with 12 and 13 wall protofilaments were present, suggesting that the ability to form a microtubule with a given number of protofilaments is inherent in the tubulin or its associated proteins. The temperature of polymerization was found to influence the number of protofilaments in resultant microtubules. With assembly at 20 degrees C, for example, most of the complete microtubules had 13 protofilaments, while at 40 degrees C most showed 10 protofilaments. It is suggested that the temperature of in vitro polymerization, among other factors, can influence the angle of binding between adjacent protofilaments and thus alter the number of protofilaments required to complete the circumference of the tubule.