副溶血性弧菌的NorM是一种由Na(+)驱动的多药外排泵。
NorM of vibrio parahaemolyticus is an Na(+)-driven multidrug efflux pump.
作者信息
Morita Y, Kataoka A, Shiota S, Mizushima T, Tsuchiya T
机构信息
Department of Microbiology, Faculty of Pharmaceutical Sciences, Okayama University, Tsushima, Okayama, 700-8530, Japan.
出版信息
J Bacteriol. 2000 Dec;182(23):6694-7. doi: 10.1128/JB.182.23.6694-6697.2000.
NorM of Vibrio parahaemolyticus apparently is a new type of multidrug efflux protein, with no significant sequence similarity to any known transport proteins. Based on the following experimental results, we conclude that NorM is an Na(+)-driven Na(+)/drug antiporter. (i) Energy-dependent ethidium efflux from cells possessing NorM was observed in the presence of Na(+) but not of K(+). (ii) An artificially imposed, inwardly directed Na(+) gradient elicited ethidium efflux from cells. (iii) The addition of ethidium to cells loaded with Na(+) elicited Na(+) efflux. Thus, NorM is an Na(+)/drug antiporting multidrug efflux pump, the first to be found in the biological world. Judging from the similarity of the NorM sequence to those of putative proteins in sequence databases, it seems that Na(+)/drug antiporters are present not only in V. parahaemolyticus but also in a wide range of other organisms.
副溶血弧菌的NorM显然是一种新型的多药外排蛋白，与任何已知转运蛋白均无显著序列相似性。基于以下实验结果，我们得出结论：NorM是一种由Na⁺驱动的Na⁺/药物反向转运体。（i）在有Na⁺但无K⁺存在的情况下，观察到具有NorM的细胞存在能量依赖性的溴化乙锭外排。（ii）人为施加的内向Na⁺梯度引发了细胞的溴化乙锭外排。（iii）向装载有Na⁺的细胞中添加溴化乙锭引发了Na⁺外排。因此，NorM是一种Na⁺/药物反向转运的多药外排泵，是在生物界发现的首个此类泵。从NorM序列与序列数据库中推定蛋白序列的相似性判断，似乎Na⁺/药物反向转运体不仅存在于副溶血弧菌中，还存在于广泛的其他生物体中。
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