First functional characterization of a singly expressed bacterial type II topoisomerase:: The enzyme from Mycohacterium wherculosis
First functional characterization of a singly expressed bacterial type II topoisomerase:: The enzyme from Mycohacterium wherculosis
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DOI：
10.1016/j.bbrc.2006.07.017
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发表时间：
2006-09-15
影响因子：
3.1
通讯作者：
Cambau, Ernmanuelle
中科院分区：
文献类型：
--
作者：
Aubry, Alexandra;Fisher, L. Mark;Cambau, Ernmanuelle
基因组破译表明，结核分枝杆菌编码一个单一的11型拓扑异构酶相反，普通细菌窝藏两个II型拓扑异构酶（DNA旋转酶和拓扑异构酶IV）。M的功能。结核11型拓扑异构酶亚单位编码基因在大肠杆菌中的克隆和表达。M.结核11型拓扑异构酶超螺旋松弛pBR 322，其比活性接近于普通细菌的DNA旋转酶，而其表现出DNA松弛和形成可切割复合物，其活性显著高于其他DNA旋转酶。动质体DNA的decatenation的分子间通过活性评价是25倍低于拓扑异构酶IV从肺炎链球菌，但显着高于大肠杆菌促旋酶。总体而言，M.结核杆菌表现出典型的DNA促旋酶的多价超螺旋活性，但增强的松弛、切割和去连环化活性。(c)2006年爱思唯尔公司All rights reserved.
Genome deciphering revealed that Mycobacterium tuberculosis encodes a single type 11 topoisomerase contrary to common bacteria harboring two type II topoisomerases (DNA gyrase and topoisomerase IV). Functions of the M. tuberculosis type 11 topoisomerase were explored after cloning and expressing the subunits encoding genes in Escherichia coli. M. tuberculosis type 11 topoisomerase supercoiled relaxed pBR322 with a specific activity close to that of DNA gyrases of common bacteria whereas it exhibited DNA relaxation and formation of cleavable complexes with activities significantly higher than other DNA gyrases. Intermolecular passage activity evaluated by the decatenation of kinetoplast DNA was 25-fold lower than that of the topoisomerase IV from Streptococcus pneumoniae, but was markedly higher than that of the E coli gyrase. Overall, the type II topoisomerase of M. tuberculosis exhibits classical polyvalent activities of DNA gyrase for supercoiling but enhanced relaxation, cleavage, and decatenation activities. (c) 2006 Elsevier Inc. All rights reserved.