Regulation of the transport system for C4-dicarboxylic acids in Bacillus subtilis
Regulation of the transport system for C4-dicarboxylic acids in Bacillus subtilis
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DOI：
10.1099/00221287-146-2-263
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发表时间：
2000-02-01
期刊：
影响因子：
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通讯作者：
Ogasawara, N
中科院分区：
文献类型：
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作者：
Asai, K;Baik, SH;Ogasawara, N
C4-二羧酸（如苹果酸、延胡索酸和琥珀酸）在革兰氏阳性菌中的转运系统尚不清楚。枯草芽孢杆菌（Bacillus subtilis）基因组全序列分析表明，它们的编码产物与革兰氏阴性菌中的C4-二羧酸结合蛋白和转运蛋白高度同源。在ydbE和ydbH之间，定位编码传感器-调节器对的基因ydbF和ydbG。失活的每一个ydbEFGH基因引起的缺陷，利用富马酸或琥珀酸，但不是苹果酸。在含有0.05%酵母提取物的最低盐培养基中刺激编码推定转运蛋白的ydbH的表达，但通过向培养基中加入苹果酸来抑制。推定的传感器-调节器对或溶质结合蛋白ydbFG或ydbE的失活导致ydbH表达的完全丧失。富马酸盐的利用和ydbH表达的刺激在ydbE无效突变体中恢复，其中ydbFGH过量产生。基于这些观察结果，结合推导产物的序列相似性分析，我们得出结论，YdbH是一个C-4-二羧酸转运蛋白，其表达受一个C-4-二羧酸传感器激酶-调节因子对YdbF和YdbG的调控。此外，有人建议，YdbE不直接参与运输的C-4-二羧酸，但在ydbF-ydbG两组分系统中起着感觉的作用，引起特异性或提高效率的系统。对ydbH启动子区的缺失分析表明，一个直接重复序列是激活ydbH表达所必需的。在启动子的-10区域还发现了分解产物响应元件（CRE），表明CRE结合蛋白的负调控。
Transport systems for C-4-dicarboxylates, such as malate, fumarate and succinate, are poorly understood in Cram-positive bacteria, The whole genome sequence of Bacillus subtilis revealed two genes, ydbE and ydbH, whose deduced products are highly homologous to binding proteins and transporters for C-4-dicarboxylates in Gram-negative bacteria. Between ydbE and ydbH, genes ydbF and ydbG encoding a sensor-regulator pair, were located. Inactivation of each one of the ydbEFGH genes caused a deficiency in utilization of fumarate or succinate but not of malate. Expression of ydbH, encoding a putative transporter, was stimulated in a minimal salt medium containing 0.05% yeast extract but repressed by the addition of malate to the medium. inactivation of the putative sensor-regulator pair or solute-binding protein, ydbFG or ydbE, caused complete loss of ydbH expression. The utilization of fumarate and stimulation of ydbH expression resumed in a ydbE null mutant in which ydbFGH were overproduced. Based on these observations, together with analysis of the sequence similarities of the deduced product, we conclude that YdbH is a C-4-dicarboxylate-transport protein and its expression is regulated by a C-4-dicarboxylate sensor kinase-regulator pair, YdbF and YdbG. Furthermore, it is suggested that YdbE does not directly participate in transport of C-4-dicarboxylates, but plays a sensory role in the ydbF-ydbG two-component system, giving rise to specificity or increased efficiency to the system. Deletion analysis of the promoter region of ydbH revealed that a direct repeat sequence was required for the activation of ydbH expression. A catabolite-responsive element (CRE) was also found in the -10 region of the promoter, suggesting negative regulation by a CRE-binding protein.