Genth H, Hofmann F, Selzer J, Rex G, Aktories K, Just I
Institut für Pharmakologie und Toxikologie der Albert-Ludwigs-Universität Freiburg, Germany.
Biochem Biophys Res Commun. 1996 Dec 13;229(2):370-4. doi: 10.1006/bbrc.1996.1812.
The hemorrhagic toxin (HT) from Clostridium sordellii is pharmacologically related to Clostridium difficile toxins A and B and Clostridium sordellii lethal toxin which have been recently identified as mono-glucosyl-transferases. Here we report that HT, which is coexpressed with lethal toxin, is also a glucosyltransferase. Whereas lethal toxin glucosylates the Rho subfamily proteins Rac and Cdc42 and the Ras subfamily proteins H-Ras and Rap, the substrate specificity of HT is strictly confined to the Rho subfamily proteins Rho, Rac and Cdc42. Comparable to lethal toxin, transferase activity of HT is stimulated by Mn2+. Acceptor amino acid in Rho was identified by mutagenesis as threonine-37. C. sordellii HT is a novel member of the family of clostridial mono-glucosyl-transferases, a family which modifies the Rho and Ras GTPases.
来自索氏梭菌的出血毒素（HT）在药理学上与艰难梭菌毒素A和B以及索氏梭菌致死毒素相关，最近已确定它们为单葡糖基转移酶。在此我们报告，与致死毒素共表达的HT也是一种葡糖基转移酶。致死毒素使Rho亚家族蛋白Rac和Cdc42以及Ras亚家族蛋白H-Ras和Rap发生葡糖基化，而HT的底物特异性严格局限于Rho亚家族蛋白Rho、Rac和Cdc42。与致死毒素类似，HT的转移酶活性受到Mn2+的刺激。通过诱变确定Rho中的受体氨基酸为苏氨酸-37。索氏梭菌HT是梭菌单葡糖基转移酶家族的一个新成员，该家族可修饰Rho和Ras GTP酶。
