Recognition of RhoA by Clostridium botulinum C3 Exoenzyme*
Recognition of RhoA by Clostridium botulinum C3 Exoenzyme*
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肉毒梭菌 C3 外切酶* 识别 RhoA
DOI：
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发表时间：
2000
影响因子：
4.8
通讯作者：
I. Just
中科院分区：
文献类型：
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作者：
C. Wilde;H. Genth;K. Aktories;I. Just
与其他Rho修饰细菌毒素相比，C3样ADP-核糖基转移酶表现出非常有限的底物特异性;它们选择性地修饰RhoA、-B和-C同种型，但不修饰Rho或Ras亚家族的其他成员。在这项研究中，参与RhoA底物识别的C3肉毒梭菌的氨基酸残基进行了鉴定，通过应用非底物Rac的突变分析。首先，负责C3识别的最小结构域被鉴定为N-末端90个残基。其次，N-末端碱性氨基酸（RhoArg 5-Lys 6）、酸性残基RhoGlu 47和RhoGlu 54的组合仅略微增加ADP-核糖基化，但完全恢复相应突变体Rac与C3的结合。第三，残基RhoGlu 40和RhoVal 43也参与与C3的结合，但它们主要参与Rho、C3和NAD+之间三元复合物的正确形成。因此，分布在Rho的N-末端部分的这6个残基（Arg 5、Lys 6、Glu 40、Val 43、Glu 47和Glu 54）参与Rho与C3的正确结合。含有这些残基的突变体Rac显示出ADP-核糖基化的动力学性质，这与RhoA的动力学性质相同。由核苷酸占有率给出的Rho构象的差异对ADP-核糖基化只有很小的影响。
The C3-like ADP-ribosyltransferases exhibit a very confined substrate specificity compared with other Rho-modifying bacterial toxins; they selectively modify the RhoA, -B, and -C isoforms but not other members of the Rho or Ras subfamilies. In this study, the amino acid residues involved in the RhoA substrate recognition by C3 from Clostridium botulinum are identified by applying mutational analyses of the nonsubstrate Rac. First, the minimum domain responsible for the recognition by C3 was identified as the N-terminal 90 residues. Second, the combination of the N-terminal basic amino acids (RhoArg5-Lys6), the acid residues RhoGlu47 andRhoGlu54 only slightly increases ADP-ribosylation but fully restores the binding of the respective mutant Rac to C3. Third, the residues RhoGlu40and RhoVal43 also participate in binding to C3 but they are mainly involved in the correct formation of the ternary complex between Rho, C3, and NAD+. Thus, these six residues (Arg5, Lys6, Glu40, Val43, Glu47, and Glu54) distributed over the N-terminal part of Rho are involved in the correct binding of Rho to C3. Mutant Rac harboring these residues shows a kinetic property with regard to ADP-ribosylation, which is identical with that of RhoA. Differences in the conformation of Rho given by the nucleotide occupancy have only minor effects on ADP-ribosylation.
影响因子：
3.5
作者：
HORTON, RM;HUNT, HD;PEASE, LR
通讯作者：
PEASE, LR