Serine suppresses the motor function of a periplasmic PomB mutation in the Vibrio flagella stator.
Serine suppresses the motor function of a periplasmic PomB mutation in the Vibrio flagella stator.
复制标题
丝氨酸抑制弧菌鞭毛定子中周质 PomB 突变的运动功能。
DOI：
10.1111/gtc.12357
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发表时间：
2016
期刊：
影响因子：
2.1
通讯作者：
Michio Homma
中科院分区：
文献类型：
--
作者：
Tatsuro Nishikino;Shiwei Zhu;Norihiro Takekawa;Seiji Kojima;Yasuhiro Onoue;Michio Homma
溶藻弧菌的鞭毛马达由两部分组成：由POMA和POMB蛋白组成的定子和以FliG为主要成分的转子。FliG和POMA之间的相互作用产生鞭毛旋转的扭矩。基于Pomb双半胱氨酸突变体的交联实验，我们先前提出Pomb周质区域的构象变化导致了定子的激活。双半胱氨酸突变体由于分子内的二硫键而失去了活力。在这项研究中，我们发现，在Pomb(L160C/I186C)突变体中加入趋化诱导剂丝氨酸，可以在不切断二硫键的情况下恢复运动能力。我们推测丝氨酸改变了转子(FliG)的构象，影响了旋转方向。结合逆时针偏向突变FliG(G214S)，Pomb(L160C/I186C)的运动能力在不添加丝氨酸的情况下得以恢复。同样，在Che−突变体中，在没有丝氨酸的情况下，无论是逆时针锁定的菌株还是顺时针(CW)锁定的菌株，运动性都得到了恢复。相比之下，在弧菌(Δ-Chey)菌株中，弧菌(L160C/I186C)需要丝氨酸才能被拯救。我们推测Chey影响定子构象，丝氨酸的运动恢复不依赖于趋化信号通路。
The flagellar motor ofVibrio alginolyticusis made of two parts: a stator consisting of proteins PomA and PomB, and a rotor whose main component is FliG. The interaction between FliG and PomA generates torque for flagellar rotation. Based on cross‐linking experiments of double‐Cys mutants of PomB, we previously proposed that a conformational change in the periplasmic region of PomB caused stator activation. Double‐Cys mutants lost their motility due to an intramolecular disulfide bridge. In this study, we found that the addition of serine, a chemotactic attractant, to a PomB(L160C/I186C) mutant restored motility without cleaving the disulfide bridge. We speculate that serine changed the rotor (FliG) conformation, affecting rotational direction. Combined with the counterclockwise (CCW)‐biased mutation FliG(G214S), motility of PomB(L160C/I186C) was restored without the addition of serine. Likewise, motility was restored without serine in Che−mutants, in either a CCW‐locked or clockwise (CW)‐locked strain. In contrast, in a ΔcheY(CCW‐locked) strain, Vibrio (L160C/I186C) required serine to be rescued. We speculate that CheY affects stator conformation and motility restoration by serine is independent on the chemotaxis signaling pathway.