PPC(Pre-Peptidase C-terminal)结构域广泛分布于分泌型海洋细菌蛋白酶的 C 末端，对蛋白酶的分泌，锚定及与底物相互吸附起到重要作用。对 PPC 结构域序列分析发现， PPC 结构域存在两个较为保守序列区，且这两个保守区空间结构为β-折叠。尽管有的PPC结构域序列一致性较低，但不同结构域间存在相同的保守序列，且其三维结构相似。为了进一步对不同来源的PPC结构域的进化关系进行系统研究，本研究选取公开发表的PPC结构域，通过在 NCBI数据库中搜索得到61条来自于39个细菌所分泌的不同蛋白酶的PPC的氨基酸序列进行系统发育分析。发现PPC结构域在生物进化过程中序列变异性大，保守性弱。其中，有些细菌PPC结构域可能来源于自身基因重复产生，有些细菌PPC结构域则可能由水平基因转移产生。%PPC (Pre-Peptidase C-terminal) domain is widely distributed in the C-terminal region of protease se-creted from marine bacterial, and it plays an important role in secretion and localization of protease, as well as ad-sorption of reaction substrate. The PPC domain sequence analysis showed that there are two conserved sequences in PPC domain amino acid sequence andβ-sheet was characterized as spatial structure of the regions. Although some PPC domain sequences show lower consistency, there are conserved sequences and similar three-dimensional structure of PPC domain. In order to analyze the evolutionary relationship of the PPC domain between different strains, this paper did phylogenetic analysis on the amino acid sequences of 61 PPC domains from 39 different stains searched from the NCBI database. The study found that PPC domain sequences were variability and noncon-servative in the biological evolution process. According to the results, some PPC domain may be derived from its gene duplication, while some may happen due to horizontal gene transfer event.
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