Functional transfer of an essential aspartate for the ion-binding site in the stator proteins of the bacterial flagellar motor

Journal of Molecular Biology
Hiroyuki TerashimaMichio Homma

Abstract

Rotation of the bacterial flagellar motor exploits the electrochemical potential of the coupling ion (H(+) or Na(+)) as its energy source. In the marine bacterium Vibrio alginolyticus, the stator complex is composed of PomA and PomB, and conducts Na(+) across the cytoplasmic membrane to generate rotation. The transmembrane (TM) region of PomB, which forms the Na(+)-conduction pathway together with TM3 and TM4 of PomA, has a highly conserved aspartate residue (Asp24) that is essential for flagellar rotation. This residue contributes to the Na(+)-binding site. However, it is not clear whether residues other than Asp24 are involved in binding the coupling ion. We examined the possibility that loss of the negative charge of Asp24 can be suppressed by introduction of negatively charged residues in TM3 or TM4 of PomA. The motility defect associated with the D24N substitution in PomB could be rescued only by a N194D substitution in PomA. This result suggests that there must be a negatively charged ion-binding pocket in the stator complex but that the presence of a negatively charged residue at position 24 of PomB is not essential. A tandemly fused PomA dimer containing the N194D mutation either in its N-terminal or C-terminal half wit...Continue Reading

References

Jul 1, 1990·Proceedings of the National Academy of Sciences of the United States of America·M J MillerR H Fillingame
Aug 11, 1995·Journal of Molecular Biology·J ZhouD F Blair
Aug 15, 1995·Proceedings of the National Academy of Sciences of the United States of America·L L SharpD F Blair
Oct 27, 1994·Nature·Y MagariyamaS Kudo
May 30, 1998·Proceedings of the National Academy of Sciences of the United States of America·J ZhouD F Blair
Feb 2, 2000·Biophysical Journal·X Chen, H C Berg
Dec 26, 2002·Annual Review of Biochemistry·Howard C Berg
Apr 2, 2005·Science·Takeshi MurataJohn E Walker
Jul 26, 2005·Journal of Molecular Biology·Hajime FukuokaMichio Homma
May 29, 2008·Proceedings of the National Academy of Sciences of the United States of America·Seiji KojimaKatsumi Imada
Dec 17, 2008·International Review of Cell and Molecular Biology·Hiroyuki TerashimaMichio Homma
Jan 28, 2009·Molecular Microbiology·Anja PaulickKai M Thormann
Feb 3, 2009·Molecular Microbiology·Hajime FukuokaMichio Homma

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Citations

Nov 28, 2012·Biochemical Society Transactions·Roland LloubèsDenis Duché
Aug 27, 2013·Journal of Bacteriology·Petra HalangJulia Steuber
Mar 10, 2010·Bioelectromagnetics·Joseph D BowmanRuiguang Song
Sep 8, 2011·Genes to Cells : Devoted to Molecular & Cellular Mechanisms·Na LiMichio Homma

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