肉毒杆菌C3外切酶介导的ADP核糖基化作用可提高重组rhoA和rhoB蛋白的稳态GTP酶活性。

ADP-ribosylation by Clostridium botulinum C3 exoenzyme increases steady-state GTPase activities of recombinant rhoA and rhoB proteins.

作者信息

Mohr C, Koch G, Just I, Aktories K

机构信息

Rudolf-Buchheim-Institut für Pharmakologie, Universität Giessen, Germany.

出版信息

FEBS Lett. 1992 Feb 3;297(1-2):95-9. doi: 10.1016/0014-5793(92)80335-e.

DOI:10.1016/0014-5793(92)80335-e

PMID:1551445

Abstract

ADP-ribosylation of recombinant rhoA and rhoB proteins by Clostridium botulinum C3 exoenzyme increased steady-state GTP hydrolysis by 50 to 80%. ADP-ribosylation and increase in GTP hydrolysis occurred at similar concentrations of C3, depended on the presence of NAD and were prevented by anti-C3 antibody or heat inactivation of C3. In contrast, GTP hydrolysis by Ile-41 rhoA or Ha-ras, which are no substrates for the transferase, were not affected by C3. ADP-ribosylation facilitated the [3H]GDP release and subsequently, the binding of [3H]GTP to rhoA. The data indicate that the increase in the steady-state GTPase activity by ADP-ribosylation is caused by increasing the rate of GDP release which is suggested to be the rate limiting step of the GTPase cycle of the small GTP-binding proteins.

摘要

肉毒梭菌C3外毒素对重组rhoA和rhoB蛋白的ADP核糖基化作用使稳态GTP水解增加了50%至80%。ADP核糖基化和GTP水解的增加在相似的C3浓度下发生，依赖于NAD的存在，并可被抗C3抗体或C3的热失活所阻止。相比之下，Ile-41 rhoA或Ha-ras（它们不是该转移酶的底物）的GTP水解不受C3影响。ADP核糖基化促进了[3H]GDP的释放，随后促进了[3H]GTP与rhoA的结合。数据表明，ADP核糖基化导致的稳态GTP酶活性增加是由于GDP释放速率的增加，而GDP释放速率被认为是小GTP结合蛋白GTP酶循环的限速步骤。