Structural effects of mutations in Salmonella typhimurium flagellar switch complex.
Structural effects of mutations in Salmonella typhimurium flagellar switch complex.
复制标题
鼠伤寒沙门氏菌鞭毛开关复合体突变的结构效应。
DOI：
10.1006/jmbi.1995.0443
复制
发表时间：
1995
影响因子：
5.6
通讯作者：
Khan,S
中科院分区：
文献类型：
--
作者：
Zhao,R;Schuster,SC;Khan,S
鼠伤寒沙门氏菌 fliG、fliMandfliN 中的突变产生非鞭毛、非运动或非趋化突变细菌。 FliG、FliM 和 FliN 蛋白构成了最近表征的延伸鞭毛基底结构的一部分，并且已被假定形成相互相互作用的结构复合物。我们通过电子显微镜和免疫印迹凝胶分析检查了来自非运动或非趋化性fliG、fliMandfliN突变株的基底体制剂。大多数从非运动突变体中分离出的鞭毛制剂缺乏 FliM，但含有 FliG。基体缺乏野生型结构的钟形形态特征，但具有可用抗FliG标记的突起。还获得了严重耗尽 FliG 但含有 FliM 的非运动突变体制剂。这些制剂包含带有抗 FliM 标记的延伸的、带钟形的鞭毛结构。因此，FliM 是负责钟形形态的延伸结构的外壳的一部分，而 FliG 可能是内部子结构的一部分。 FliG 温度敏感突变株的扩展基础结构在转移到不允许的温度时迅速失去 FliM 和 FliG，这意味着包含 FliG 和 FliM 的子结构之间存在相互作用。与非运动突变体形成鲜明对比的是，从非趋化突变体中分离出的扩展基础结构与野生型结构无法区分。这种差异可能反映了在扭矩产生和旋转方向切换过程中不同蛋白质-蛋白质相互作用的能量学。
Mutations inSalmonella typhimurium fliG, fliMandfliNgive rise either to non-flagellate, non-motile or non-chemotactic mutant bacteria. The FliG, FliM and FliN proteins form part of recently characterized extended flagellar basal structures, and have been postulated to form a mutually interacting structural complex. We have examined basal body preparations from non-motile or non-chemotacticfliG, fliMandfliNmutant strains by electron microscopy and immunoblot gel analysis. Most flagellar preparations isolated from the non-motile mutants lacked FliM, but contained FliG. The basal bodies lacked the belled morphology characteristic of the wild-type structures, but had protrusions which could be labelled with anti-FliG. Non-motile mutant preparations severely depleted of FliG but containing FliM were also obtained. These preparations contained extended, belled flagellar structures that were labelled with anti-FliM. Thus, FliM is part of the shell of the extended structures responsible for the belled morphology, while FliG may be part of the inner substructure. The extended basal structures from a FliG temperature-sensitive mutant strain rapidly lost FliM, as well as FliG, upon a shift to a non-permissive temperature, implying interaction between the FliG- and FliM-containing substructures. In dramatic contrast to non-motile mutants, extended basal structures isolated from non-chemotactic mutants were indistinguishable from wild-type structures. This difference may reflect the energetics of the different protein–protein interactions operative during torque generation and the switching of rotation sense.