초고온성 아케아 써모코커스 NA1으로부터 펩티다제의 특성

Abstract

Thermococcus sp. NA1 is one of the hyperthermophilic archaea collected from a deep-sea hydrothermal vent area at the PACMANUS field in the EAST Manus Basin. As a part of genomic research of the Thermococcus sp. NA1, genes which had high sequence similarity to the genes encoding the peptidases (prolyl aminopeptidase, methionyl aminopeptidase, prolyl endopeptidase, and carboxypeptidase) from Thermococcus kodakaraensis KOD1 (74%, 85%, 83%, and 90% identity, respectively) were revealed. The genes encoding prolyl aminopeptidase, methionyl aminopeptidase, prolyl endopeptidase, and carboxypeptidase comprise open reading frames of 1,071 bp, 888 bp, 1,851 bp, and 1,500 bp, corresponding to polypeptides of 356, 295, 616, and 499 amino acids with predicted molecular mass of 39,713 Da, 32,981 Da, 70,380 Da, and 59,197 Da, respectively. To characterize the peptidases, the genes were cloned and overexpressed in Escherichia coli with the pET vector system, and the expressed enzymes had high hydrolytic activities for peptidases at high temperatures. Substrate specificity, inhibitor sensitivity, temperature and pH dependence, and metal ion requirement for enzyme activity were examined and their inherent biotechnological potentials were investigated.