摘要
为了研究嗜甲基菌（Methylophilus）DM11菌株二氯甲烷脱卤素酶的不同氨基酸残基在底物结合、谷胱甘肽（GSH）亲和以及催化活力中的作用，对编码该酶的基因进行了定点诱变研究。将保守的103位色氨酸（W）分别用苯丙氨酸（F）、缬氨酸（V）或天冬酞胺（N）替换，109位精氨酸（R）用亮氨酸（L）替换，117位色氨酸用酪氨酸（Y）或苯丙氨酸替换，得到6种突变酶。其中3种突变酶具有较低的活力，另外3种突变酶没有活力。突变酶W117Y的性质与野生型酶明显不同。
In order to investigate the role of different residues of Methylophilus sp.strain DM11 dichloromethane dehalogenase for substrate binding, glutatione affinity,and catalytic activity, site-directed mutagenesis studies of the gene encoding the enzyme were carried ouL The conserved tryptophane residue at 103 region was respectively substituted by phenylalanine, valine or asparagine. The conserved arginine residue at 109 region was substituted by leucine. The conserved tryptophane residue at 117 region was respectively substituted by tyrosine or phenylaleine. Six mutant enzymes were propuced. Among them three possess lower activities, other three do not possess activity. The properties of the mutant enzyme W117Y are very different from wild-type enzyme.
出处
《微生物学报》
CAS
CSCD
北大核心
1998年第3期163-167,共5页
Acta Microbiologica Sinica
基金
国家自然科学基金
天津市自然科学基金
关键词
嗜甲基菌
二氯甲烷
脱卤素酶
定点诱变
突变酶
Methylophilus sp., Dichloromethane dehalogenase, Site-directed mutagenesis, Mutant enzyme
