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首页> 外文期刊>Journal of bacteriology >Interactions between a Bacillus subtilis anti-sigma factor (RsbW) and its antagonist (RsbV).
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Interactions between a Bacillus subtilis anti-sigma factor (RsbW) and its antagonist (RsbV).

机译：枯草芽孢杆菌抗-sigma因子（RsbW）和其拮抗剂（RsbV）之间的相互作用。

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The activity of sigma B, a secondary sigma factor of Bacillus subtilis, is primarily controlled by an anti-sigma factor protein (RsbW) that binds to sigma B and blocks its ability to form an RNA polymerase holoenzyme (E-sigma B). Inhibition of sigma B by RsbW is counteracted by RsbV, a protein that is essential for the activation of sigma B-dependent transcription. When crude B. subtilis extracts were fractionated by gel filtration chromatography or electrophoresis through nondenaturing polyacrylamide gels, a complex composed of RsbW and RsbV that is distinct from the previously observed RsbW-sigma B complex was detected. In analogous experiments, RsbX, an additional regulator of sigma B-dependent transcription that is thought to act independently of RsbV-RsbW, was not found to associate with any of the other sigB operon products. Two forms of RsbV were visualized when crude cell extracts of B. subtilis were subjected to isoelectric focusing (IEF), with the more negatively charged RsbV species absent from extracts prepared from RsbW- strains. In vitro, RsbV became phosphorylated when incubated with ATP and RsbW but not with ATP alone. The phosphorylated RsbV species comigrated during IEF with the RsbW-dependent form of RsbV found in crude cell extracts. These results suggest that the modified RsbV, present in crude cell extracts, is phosphorylated. When gel filtration fractions containing RsbV-RsbW complexes or RsbV alone were subjected to IEF, only the unmodified form of RsbV was found associated with RsbW. The presumed phosphorylated variant of RsbV was present only in fractions that did not contain RsbW. The data support a model whereby RsbV binds directly to RsbW and blocks its ability to form the RsbW-sigma B complex. This activity of RsbV appears to be inhibited by RsbW-dependent phosphorylation.
机译：枯草芽孢杆菌的第二个sigma因子sigma B的活性主要受与sigma B结合并阻止其形成RNA聚合酶全酶（E-sigma B）的抗sigma因子蛋白（RsbW）控制。 RsbW对σB的抑制作用被RsbV抵消，RsbV是激活σB依赖性转录所必需的蛋白质。当通过凝胶过滤色谱法或通过非变性聚丙烯酰胺凝胶电泳对枯草芽孢杆菌提取物进行分级分离时，检测到由RsbW和RsbV组成的复合物不同于先前观察到的RsbW-sigma B复合物。在类似的实验中，未发现RsbX是sigma B依赖性转录的另外一种调节因子，认为其独立于RsbV-RsbW起作用，未与任何其他sigB操纵子产物缔合。当对枯草芽孢杆菌的粗细胞提取物进行等电聚焦（IEF）时，可以看到两种形式的RsbV，而从RsbW-菌株制备的提取物中不存在带更多负电荷的RsbV。在体外，当与ATP和RsbW一起孵育而不是与ATP单独孵育时，RsbV会被磷酸化。磷酸化的RsbV物种在IEF期间与在粗细胞提取物中发现的RsbV依赖形式的RsbV发生了迁移。这些结果表明存在于粗细胞提取物中的修饰的RsbV被磷酸化。当对包含RsbV-RsbW复合物或单独的RsbV的凝胶过滤部分进行IEF时，仅发现未修饰形式的RsbV与RsbW相关。推测的RsbV磷酸化变异体仅以不含RsbW的馏分形式存在。数据支持一个模型，其中RsbV直接绑定到RsbW并阻止其形成RsbW-sigma B复合体的能力。 RsbV的这种活性似乎受到RsbW依赖性磷酸化的抑制。

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