title: Proton-conductivity assay of plugged and unplugged MotA/B proton channel by cytoplasmic pHluorin expressed in Salmonella.
abstract: MotA and MotB form the proton-channel complex of the proton-driven bacterial flagellar motor. A plug segment of Escherichia coli MotB suppresses proton leakage through the MotA/B complex when it is not assembled into the motor. Using a ratiometric pH indicator protein, pHluorin, we show that the proton-conductivity of a Salmonella MotA/B complex not incorporated into the motor is two orders of magnitude lower than that of a complex that is incorporated and activated. This leakage is, however, significant enough to change the cytoplasmic pH to a level at which the chemotaxis signal transduction system responds.
authors.affiliation: Graduate School of Frontier Biosciences, Osaka University, Suita, Osaka, Japan.
authors.forename: Yusuke V
authors.initials: YV
authors.lastname: Morimoto
authors.forename: Yong-Suk
authors.initials: YS
authors.lastname: Che
authors.forename: Tohru
authors.initials: T
authors.lastname: Minamino
authors.forename: Keiichi
authors.initials: K
authors.lastname: Namba
mesh_terms: D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D001431:Bacteriological Techniques; D003593:Cytoplasm / Q000235:genetics / Q000378:metabolism; D004553:Electric Conductivity; D005456:Fluorescent Dyes / Q000378:metabolism / Q000494:pharmacology; D015964:Gene Expression Regulation, Bacterial; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism* / Q000494:pharmacology; D006863:Hydrogen-Ion Concentration; D046912:Multiprotein Complexes / Q000737:chemistry / Q000378:metabolism; D020125:Mutation, Missense; D017494:Proton Pumps / Q000737:chemistry / Q000378:metabolism / Q000502:physiology; D011522:Protons; D019779:Salmonella enterica / Q000235:genetics / Q000378:metabolism* / Q000502:physiology
chemical_list: D001426:Bacterial Proteins; D005456:Fluorescent Dyes; C063010:MotA protein, Bacteria; C064779:MotB protein, Bacteria; D046912:Multiprotein Complexes; C485187:PHluorin; D017494:Proton Pumps; D011522:Protons; D049452:Green Fluorescent Proteins