Mutational analysis of parasite trypanothione reductase: acquisition of glutathione reductase activity in a triple mutant.
Mutational analysis of parasite trypanothione reductase: acquisition of glutathione reductase activity in a triple mutant.
复制标题
寄生虫锥硫酮还原酶的突变分析：在三重突变体中获得谷胱甘肽还原酶活性。
DOI：
10.1021/bi00225a004
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发表时间：
1991
期刊：
影响因子：
2.9
通讯作者：
Walsh,CT
中科院分区：
文献类型：
--
作者：
Sullivan,FX;Sobolov,SB;Bradley,M;Walsh,CT
马萨诸塞州波士顿哈佛医学院生物化学和分子药理学教研室，1990年9月12日收到；修订稿件收到1990年11月28日。摘要：非洲锥虫体内含有氧化谷胱甘肽的环衍生物，TV‘。亚精胺，称为色硫酮。这是寄生虫酶台盼硫酮还原酶的底物，台盼硫酮还原酶是二硫化物/二硫醇氧化还原平衡的关键酶，也是锥虫杀灭治疗的靶酶。这些锥虫和相关锥虫的锥硫酮还原酶在结构上与宿主谷胱甘肽还原酶同源，但这两种酶表现出相互排斥的底物特异性。为了评估宿主和寄生虫酶对其二硫化物底物的识别基础，以结合谷胱甘肽与先前X射线分析所定义的人红细胞谷胱甘肽还原酶活性部位残基的相互作用为起点，对黄牛寄生虫锥虫的锥虫还原酶的三个残基进行了诱变。三个氨基酸的突变从根本上改变了酶的特异性，并允许获得比野生型台盼硫还原酶高出104水平的谷胱甘肽还原酶活性。
Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts 02115 Received September 12, 1990; Revised Manuscript Received November 28, 1990 abstract: African trypanosomes contain a cyclic derivative of oxidized glutathione, TV'. A^-bisfglutathionyl) spermidine, termed trypanothione. This is the substrate for the parasite enzyme trypanothione reductase, a key enzyme in disulfide/dithiol redox balance and a target enzyme for trypanocidal therapy. Trypanothione reductase from these andrelated trypanosomatid parasites is structurally homologous to host glutathione reductase but the two enzymes show mutually exclusive substrate specificities. To assess the basis of host vs parasite enzyme recognition fortheir disulfide substrates, the interaction of bound glutathione with active-site residues in human red cell glutathione reductase as defined by prior X-ray analysis was used as the starting point for mutagenesis of three residues in trypanothione reductase from Trypanosoma congolense, a cattle parasite. Mutation of threeresidues radically alters enzyme specificity and permits acquisition of glutathione reductase activity at levels 104 higher than in wild-type trypanothione reductase.