Sokabe Masaaki, Kawamura Takashi, Sakai Naoki, Yao Min, Watanabe Nobuhisa, Tanaka Isao
Division of Biological Sciences, Graduate School of Science, Hokkaido University, Sapporo 060-0810, Japan.
J Struct Funct Genomics. 2002;2(3):145-54. doi: 10.1023/a:1021257701676.
The crystal structure of pyrrolidone-carboxylate peptidase (PCP) from hyperthermophilic archaea Pyrococcus horikoshii (PhoPCP) has been determined at 1.6-A resolution by X-ray crystallography. PCP belongs to the C15 family of cysteine protease, and specifically removes the amino terminal pyroglutamate residue from a wide range of N-terminal-blocking peptides. The crystal structure is very similar to that of other hyperthermophiles, Pyrococcus furiosus and Thermococcus litoralis, and even that from the mesophile, Bacillus amyloliquefaciens. The inter-subunit disulfide bonds, which have been proposed as one of the thermostabilizing factors of the PCP from such hyperthermophiles, was not present in PhoPCP. The result suggests that the thermostability of PhoPCP may be obtained by the accumulation of many weak factors.
嗜热古菌火之神栖热袍菌（PhoPCP）的吡咯烷酮羧肽酶（PCP）晶体结构已通过X射线晶体学在1.6埃分辨率下测定。PCP属于半胱氨酸蛋白酶的C15家族，可特异性地从多种N端封闭肽中去除氨基末端焦谷氨酸残基。该晶体结构与其他嗜热菌，如激烈火球菌和嗜热栖热菌，甚至与嗜温菌解淀粉芽孢杆菌的晶体结构非常相似。在嗜热菌中被认为是PCP热稳定因素之一的亚基间二硫键在PhoPCP中并不存在。结果表明，PhoPCP的热稳定性可能是由许多弱因素的积累获得的。
