对提高黄杆菌属尼龙寡聚物降解酶催化活性至关重要的氨基酸改变

Amino acid alterations essential for increasing the catalytic activity of the nylon-oligomer-degradation enzyme of Flavobacterium sp.

作者信息

Kato K, Fujiyama K, Hatanaka H S, Priyambada I D, Negoro S, Urabe I, Okada H

机构信息

Department of Fermentation Technology, Osaka University, Japan.

出版信息

Eur J Biochem. 1991 Aug 15;200(1):165-9. doi: 10.1111/j.1432-1033.1991.tb21063.x.

DOI:10.1111/j.1432-1033.1991.tb21063.x

PMID:1879421

Abstract

The structural genes of two homologous enzymes, 6-aminohexanoate-dimer hydrolase (EII; nylB) and its evolutionally related protein EII' (nylB') of Flavobacterium sp. KI72 have an open reading frame encoding a peptide of 392 amino acids, of which 47 are different, and conserved restriction sites. The specific activity of EII towards 6-aminohexanoate dimer is about 1000-fold that of EII'. Construction of various hybrid genes obtained by exchanging fragments flanked by conserved restriction sites of the two genes demonstrated that two amino acid replacements in the EII' enzyme, i.e. Gly181----Asp (EII type) and His266----Asn (EII type), enhanced the activity toward 6-aminohexanoate dimer 1000-fold.

摘要

黄杆菌属KI72菌株的两种同源酶，6-氨基己酸二聚体水解酶（EII；尼龙酶B）及其进化相关蛋白EII'（尼龙酶B'）的结构基因具有一个开放阅读框，编码一个由392个氨基酸组成的肽段，其中47个氨基酸不同，并且有保守的限制性酶切位点。EII对6-氨基己酸二聚体的比活性约为EII'的1000倍。通过交换两个基因保守限制性酶切位点侧翼片段构建的各种杂交基因表明，EII'酶中的两个氨基酸替换，即Gly181→Asp（EII型）和His266→Asn（EII型），使对6-氨基己酸二聚体的活性提高了1000倍。