期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：1977
卷号：74
期号：10
页码：4375-4377
DOI：10.1073/pnas.74.10.4375
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：Tubulin dimers isolated from brain contain two GTP binding sites, a nonexchangeable site and an exchangeable site. To localize the exchangeable site, we used a photoaffinity analog of GTP, 8-azidoguanosine triphosphate (8-N3GTP), which supports tubulin polymerization in the absence of activating light. Photolysis of tubulin polymerized in the presence of 0.01 to 0.1 mM [beta, gamma-32P]8-N3GTP resulted in covalent incorporation of radioactivity only onto the beta monomer. Photolysis with 8-N3GTP also prevented any further repolymerization of the tubulin whereas like treatment in the presence of GTP had no effect. Preincubation of tubulin with GTP prevented photo-incorporation of [beta, gamma-32P]8-N3GTP whereas preincubation with ATP did not.
