The ATP binding cassette multidrug transporter LmrA and lipid transporter MsbA have overlapping substrate Specificities
The ATP binding cassette multidrug transporter LmrA and lipid transporter MsbA have overlapping substrate Specificities
复制标题
DOI：
10.1074/jbc.m306226200
复制
发表时间：
2003-09-12
影响因子：
4.8
通讯作者：
van Veen, HW
中科院分区：
文献类型：
--
作者：
Reuter, G;Janvilisri, T;van Veen, HW
LmrA是乳酸乳球菌中的ATP结合盒（ABC）多药转运蛋白，是人多药耐药P-糖蛋白MDR 1（ABCB 1）的结构和功能同源物。LmrA也与MsbA同源，MsbA是大肠杆菌中参与脂质（包括脂质A）运输的一种必需ABC转运蛋白。我们详细比较了LmrA和MsbA的底物特异性。令人惊讶的是，LmrA能够在功能上替代E. coliWD 2在非允许温度下的表达，表明LmrA可以转运Lipid A。LmrA还表现出脂质A刺激的钒酸盐敏感的ATP酶活性。反过来，MsbA的表达赋予大肠杆菌多药耐药。杆菌与LmrA类似，MsbA与光活化底物[H-3]叠氮平相互作用，显示柔红霉素、长春碱和Hoechst 33342刺激的钒酸盐敏感性ATP酶活性，并介导来自细胞的乙锭和Hoechst 33342在含有纯化和功能重建蛋白的蛋白脂质体中的转运。总之，这些数据表明MsbA和LmrA具有重叠的底物特异性。我们的观察结果暗示了最近发表的MsbA在E.大肠杆菌和霍乱弧菌（Chang，G.，和Roth，C. B。（2001）Science 293，1793 - 1800; Chang，G.等人（2003）J. Mol. Biol.330，419 - 430），其支持药物-蛋白质相互作用并提示LmrA在L.乳酸菌。
LmrA is an ATP binding cassette (ABC) multidrug transporter in Lactococcus lactis that is a structural and functional homologue of the human multidrug resistance P-glycoprotein MDR1 (ABCB1). LmrA is also homologous to MsbA, an essential ABC transporter in Escherichia coli involved in the trafficking of lipids, including Lipid A. We have compared the substrate specificities of LmrA and MsbA in detail. Surprisingly, LmrA was able to functionally substitute for a temperature-sensitive mutant MsbA in E. coli WD2 at non-permissive temperatures, suggesting that LmrA could transport Lipid A. LmrA also exhibited a Lipid A-stimulated, vanadate-sensitive ATPase activity. Reciprocally, the expression of MsbA conferred multidrug resistance on E. coli. Similar to LmrA, MsbA interacted with photoactivatable substrate [H-3] azidopine, displayed a daunomycin, vinblastine, and Hoechst 33342-stimulated vanadate- sensitive ATPase activity, and mediated the transport of ethidium from cells and Hoechst 33342 in proteoliposomes containing purified and functionally reconstituted protein. Taken together, these data demonstrate that MsbA and LmrA have overlapping substrate specificities. Our observations imply the presence of structural elements in the recently published crystal structures of MsbA in E. coli and Vibrio cholera (Chang, G., and Roth, C. B. (2001) Science 293, 1793 - 1800; Chang, G. (2003) J. Mol. Biol. 330, 419 - 430) that support drug-protein interactions and suggest a possible role for LmrA in lipid trafficking in L. lactis.