Assessment of the requirements for magnesium transporters in Bacillus subtilis.
Assessment of the requirements for magnesium transporters in Bacillus subtilis.
复制标题
评估枯草芽孢杆菌中镁转运蛋白的要求。
DOI：
10.1128/jb.01238-13
复制
发表时间：
2014
影响因子：
3.2
通讯作者：
Winkler,WadeC
中科院分区：
文献类型：
--
作者：
Wakeman,CatherineA;Goodson,JonathanR;Zacharia,VineethaM;Winkler,WadeC
镁是细胞中含量最丰富的二价金属，是许多结构和酶功能所必需的。对于细菌来说，至少有三个蛋白质家族起着镁转运体的作用。近年来，研究表明，这些转运蛋白的一部分受镁反应基因控制元件的调控。在这项研究中，我们调查了模式微生物枯草芽孢杆菌对镁动态平衡的细胞需求。假定的镁转运蛋白基因被突变打乱，单个和组合，以评估它们的普遍重要性。这些基因中只有一个的突变导致了对补充细胞外镁的强烈依赖。值得注意的是，这种转运蛋白基因mgtE已知处于镁反应基因调控之下。这表明，对镁的反应遗传机制的鉴定可能通常表示细菌的主要运输蛋白。为了研究枯草杆菌是否编码其他类别的运输机制，我们鉴定了允许转运蛋白缺陷突变株生长的抑制菌株。对其中几个菌株进行了测序，以确定抑制表型的遗传基础。这些突变都没有发生在运输蛋白同源物中；相反，它们影响了管家功能，如信号识别颗粒成分和ATP合成酶机制。根据这些综合数据，我们推测gtE蛋白提供了枯草杆菌镁输入的主要途径，其他假定的运输蛋白可能被用于更专业化的生长条件。
Magnesium is the most abundant divalent metal in cells and is required for many structural and enzymatic functions. For bacteria, at least three families of proteins function as magnesium transporters. In recent years, it has been shown that a subset of these transport proteins is regulated by magnesium-responsive genetic control elements. In this study, we investigated the cellular requirements for magnesium homeostasis in the model microorganism Bacillus subtilis. Putative magnesium transporter genes were mutationally disrupted, singly and in combination, in order to assess their general importance. Mutation of only one of these genes resulted in strong dependency on supplemental extracellular magnesium. Notably, this transporter gene,mgtE, is known to be under magnesium-responsive genetic regulatory control. This suggests that the identification of magnesium-responsive genetic mechanisms may generally denote primary transport proteins for bacteria. To investigate whether B. subtilis encodes yet additional classes of transport mechanisms, suppressor strains that permitted the growth of a transporter-defective mutant were identified. Several of these strains were sequenced to determine the genetic basis of the suppressor phenotypes. None of these mutations occurred in transport protein homologues; instead, they affected housekeeping functions, such as signal recognition particle components and ATP synthase machinery. From these aggregate data, we speculate that themgtEprotein provides the primary route of magnesium import in B. subtilis and that the other putative transport proteins are likely to be utilized for more-specialized growth conditions.