title: Construction of functional fragments of the cytoplasmic loop with the C-terminal region of PomA, a stator component of the Vibrio Na+ driven flagellar motor.
abstract: The membrane motor proteins, PomA (polar flagellar motility protein A) and PomB (polar flagellar motility protein B), of Vibrio alginolyticus form a stator complex that converts energy from the ion flow to mechanical work in bacterial flagellar motors. The cytoplasmic domain of PomA is believed to interact with the rotor protein FliG to make a torque. In this study, to investigate the function of the cytoplasmic domain of PomA, we constructed a series of fragments that flank the cytoplasmic loop of PomA between the second and third transmembrane (TM) domains (A-loop) and the C-terminal region, and expressed them in Escherichia coli together with PomA and PotB (a chimeric protein of PomB and MotB). We observed a dominant-negative effect of one PomA fragment on motility. We confirmed that these PomA fragments localized both in the membrane fraction and in the cytoplasmic fraction, and induced bacterial growth delay. Effect of additional point and deletion mutations into this fragment implies that the C-terminal region and TM domains used as a linker play a significant part in these observations. From these results, we conclude that the PomA fragments retain the structure important for functions. We expect that further constructions will provide a variety of experimental approaches to characterize the interaction between PomA and FliG.
authors.affiliation: Division of Biological Science, Graduate School of Science, Nagoya University, Chikusa-ku, Nagoya 464-8602, Japan.
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Onoue
authors.forename: Rei
authors.initials: R
authors.lastname: Abe-Yoshizumi
authors.forename: Mizuki
authors.initials: M
authors.lastname: Gohara
authors.forename: Shiori
authors.initials: S
authors.lastname: Kobayashi
authors.forename: Noriko
authors.initials: N
authors.lastname: Nishioka
authors.forename: Seiji
authors.initials: S
authors.lastname: Kojima
authors.forename: Michio
authors.initials: M
authors.lastname: Homma
mesh_terms: D001426:Bacterial Proteins / Q000737:chemistry* / Q000378:metabolism*; D017124:Conserved Sequence; D003593:Cytoplasm / Q000378:metabolism; D004926:Escherichia coli / Q000254:growth & development / Q000378:metabolism; D005407:Flagella / Q000378:metabolism*; D009068:Movement; D050505:Mutant Proteins / Q000737:chemistry / Q000378:metabolism; D009154:Mutation / Q000235:genetics; D011485:Protein Binding; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D011993:Recombinant Fusion Proteins / Q000378:metabolism*; D017384:Sequence Deletion; D012964:Sodium / Q000378:metabolism*; D015222:Sodium Channels / Q000737:chemistry* / Q000378:metabolism*; D044149:Vibrio alginolyticus / Q000378:metabolism*
chemical_list: D001426:Bacterial Proteins; D050505:Mutant Proteins; C107540:PomA protein, Vibrio; D011993:Recombinant Fusion Proteins; D015222:Sodium Channels; D012964:Sodium
keywords: Vibrio; bacterial flagellum; ion-driven motor; motor protein; stator