肺炎克雷伯菌中的一种新型I型限制修饰系统KpnAI。

KpnAI, a new type I restriction-modification system in Klebsiella pneumoniae.

作者信息

Lee N S, Rutebuka O, Arakawa T, Bickle T A, Ryu J

机构信息

Department of Microbiology and Molecular Genetics, School of Medicine, Loma Linda, CA 92350, USA.

出版信息

J Mol Biol. 1997 Aug 22;271(3):342-8. doi: 10.1006/jmbi.1997.1202.

DOI:10.1006/jmbi.1997.1202

PMID:9268663

Abstract

The KpnAI restriction-modification (R-M) system has been identified in Klebsiella pneumoniae strain M5a1. The restriction gene of KpnAI was first cloned into pBR322 using an r-m+ M5a1 derivative and phage SBS for screening. Subsequently, an adjacent DNA fragment showing modification activity was cloned into pUC19. A total of 7.2 kb DNA sequencing data revealed three open reading frames, corresponding to hsdR, hsdM and hsdS genes of type I R-M systems. The predicted hsdR, hsdM and hsdS-coded peptides shared 95%, 98% and 44% identity, respectively, with the corresponding peptides of the recently identified StySBLI system, a prototype of the type ID family. This high homology suggests that KpnAI is also a member of the type ID family. The KpnAI system seems to be the first type I system identified in Klebsiella species.

摘要

已在肺炎克雷伯菌M5a1菌株中鉴定出KpnAI限制修饰（R-M）系统。利用r-m+ M5a1衍生物和噬菌体SBS进行筛选，首次将KpnAI的限制基因克隆到pBR322中。随后，将一个显示修饰活性的相邻DNA片段克隆到pUC19中。总共7.2 kb的DNA测序数据揭示了三个开放阅读框，分别对应于I型R-M系统的hsdR、hsdM和hsdS基因。预测的由hsdR、hsdM和hsdS编码的肽分别与最近鉴定的StySBLI系统（ID型家族的原型）的相应肽具有95%、98%和44%的同一性。这种高度同源性表明KpnAI也是ID型家族的成员。KpnAI系统似乎是在克雷伯菌属中鉴定出的首个I型系统。