Activation of glycosylasparaginase - Formation of active N-terminal threonine by intramolecular autoproteolysis
Activation of glycosylasparaginase - Formation of active N-terminal threonine by intramolecular autoproteolysis
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DOI：
10.1074/jbc.271.3.1732
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发表时间：
1996-01-19
影响因子：
4.8
通讯作者：
Comb, D
中科院分区：
文献类型：
--
作者：
Guan, CD;Cui, T;Comb, D
采用定点诱变和纯化前体体外活化的方法，分析了脑膜败血黄杆菌糖基天冬酰胺酶的激活机制。Thr-152突变为丝氨酸或半胱氨酸导致基因产物在体内不被激活，但在体外被激活。由于突变前体的加工被细胞中的某些氨基酸抑制，动力学研究表明激活是一个分子内的自我蛋白分解过程。His150和Thr/Ser/Cys-152参与激活表明，自身蛋白分解类似于丝氨酸/半胱氨酸蛋白酶的蛋白分解。高度保守的活性苏氨酸残基具有多种功能。
The activation mechanism of glycosylasparaginase of Flavobacterium meningosepticum has been analyzed by site directed mutagenesis and activation of purified precursors in vitro. Mutation of Thr-152 to Ser or Cys leads to gene products that are not activated in vivo but are activated in vitro because processing of the mutant precursors is inhibited by certain amino acids in the cell, Kinetic studies reveal that activation is an intramolecular autoproteolytic process. The involvement of His150 and Thr/Ser/Cys-152 in activation suggests that autoproteolysis resembles proteolysis by serine/cysteine proteases. Multiple functions of the highly conserved active threonine residue are implicated.