Owens Marie U, Swords W Edward, Schmidt Michael G, King C Harold, Quinn Frederick D
Tuberculosis/Mycobacteriology Branch, Centers for Disease Control and Prevention, Bldg. 17, Room 4029, Mailstop FO8, Atlanta, GA 30333, USA.
FEMS Microbiol Lett. 2002 Jun 4;211(2):133-41. doi: 10.1111/j.1574-6968.2002.tb11215.x.
To better understand the protein secretion mechanisms involved in the growth and pathogenesis of Mycobacterium tuberculosis, we examined the secA gene from M. tuberculosis (tbsecA; cosmid sequence accession No. z95121.gb_ba). We generated plasmids containing the full-length tbsecA gene or a fusion containing the 5' sequence from the M. tuberculosis secA gene and the remainder from the Escherichia coli secA gene and evaluated the ability of each construct to complement the defective SecA protein in E. coli MM52ts when grown at the non-permissive temperature. The full-length tbsecA gene was unable to compensate for the temperature-sensitive defect, whereas E. coli MM52ts that has been transformed with plasmid pMF8TB226 containing a chimeric secA gene was able to grow at 42 degrees C. This work confirms that the topography of SecA and its ATP binding sites are highly conserved, whereas its membrane insertion domains are species specific.
为了更好地理解参与结核分枝杆菌生长和发病机制的蛋白质分泌机制，我们研究了结核分枝杆菌的secA基因（tbsecA；黏粒序列登录号z95121.gb_ba）。我们构建了含有全长tbsecA基因的质粒，或含有来自结核分枝杆菌secA基因5'序列与来自大肠杆菌secA基因其余部分的融合质粒，并评估了每个构建体在非允许温度下生长时互补大肠杆菌MM52ts中缺陷性SecA蛋白的能力。全长tbsecA基因无法弥补温度敏感缺陷，而用含有嵌合secA基因的质粒pMF8TB226转化的大肠杆菌MM52ts能够在42℃生长。这项工作证实，SecA的拓扑结构及其ATP结合位点高度保守，而其膜插入结构域具有物种特异性。
