微管蛋白聚集的准弹性光散射研究

Quasielastic light scattering studies of tubulin aggregation.

作者信息

Howard W, Timasheff S N

出版信息

Arch Biochem Biophys. 1987 Jun;255(2):446-52. doi: 10.1016/0003-9861(87)90413-9.

Abstract

A quasielastic light scattering study of purified tubulin has resulted in a monomer diffusion coefficient of 6.0 X 10(-7) cm2/s. In an attempt to characterize the small tubulin oligomers which are predicted to form as intermediates in the self-assembly into double rings, magnesium ions (10 mM) were incorporated into the PG (10 mM NaPi, 0.1 mM GTP, pH 7.0) buffer. With magnesium-containing buffers, a second slow diffusing species was identified with D = 0.56 X 10(-7) cm2/s. This corresponds to the tubulin double rings. A study of the small oligomers was precluded by the presence in all preparations of traces of aggregates resulting from the slow aging process of the protein (V. Prakash and S. N. Timasheff (1982) J. Mol. Biol. 160, 499-515). While colchicine was shown to inhibit this aging process, the presence of these irreversible aggregates, even to the extent of 1% by mass, precludes equilibrium studies of the self-association of tubulin into small oligomers.

摘要

对纯化微管蛋白进行的准弹性光散射研究得出单体扩散系数为6.0×10⁻⁷ cm²/s。为了表征预计会作为自组装成双环中间体形成的小微管蛋白寡聚体，将镁离子（10 mM）加入到PG（10 mM磷酸钠、0.1 mM GTP、pH 7.0）缓冲液中。使用含镁缓冲液时，鉴定出了第二种慢扩散物质，其扩散系数D = 0.56×10⁻⁷ cm²/s。这对应于微管蛋白双环。由于蛋白质缓慢老化过程在所有制剂中都会产生痕量聚集体（V. Prakash和S. N. Timasheff（1982年）《分子生物学杂志》160卷，499 - 515页），因此无法对小微管蛋白寡聚体进行研究。虽然秋水仙碱被证明可抑制这种老化过程，但这些不可逆聚集体的存在，即使质量分数仅为1%，也排除了对微管蛋白自缔合形成小微管蛋白寡聚体的平衡研究。