在肺炎克雷伯菌中发现了一种新的限制修饰系统KpnBI。

A new restriction-modification system, KpnBI, recognized in Klebsiella pneumoniae.

作者信息

Valinluck B, Lee N S, Ryu J

机构信息

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

出版信息

Gene. 1995 Dec 29;167(1-2):59-62. doi: 10.1016/0378-1119(95)00660-5.

DOI:10.1016/0378-1119(95)00660-5

PMID:8566812

Abstract

A unique DNA restriction-modification (R-M) system has been identified in the GM236 strain of Klebsiella pneumoniae using the newly isolated phage, SBS. The system was designated KpnBI. The gene (hsdRKpnBI) complementing the restriction activity of the KpnBI system was cloned in pBR322. The nucleotide sequence of the cloned DNA revealed one open reading frame (ORF) of 3035 bp. Analysis of the deduced amino-acid sequence shows seven helicase motifs which are common to the restriction (R) subunit of both type-I and type-III R-M systems. Computer analysis (Dendrogram) of the R polypeptide of KpnBI suggests a closer relationship to EcoR124/3I, a member of type-IC family, than to other representative type-I and type-III systems.

摘要

利用新分离的噬菌体SBS，在肺炎克雷伯菌GM236菌株中鉴定出一种独特的DNA限制修饰（R-M）系统。该系统被命名为KpnBI。补充KpnBI系统限制活性的基因（hsdRKpnBI）被克隆到pBR322中。克隆DNA的核苷酸序列显示有一个3035 bp的开放阅读框（ORF）。对推导的氨基酸序列分析表明，有七个解旋酶基序，这是I型和III型R-M系统的限制（R）亚基所共有的。对KpnBI的R多肽进行计算机分析（系统发育树）表明，它与IC型家族成员EcoR124/3I的关系比与其他代表性的I型和III型系统更密切。