Abstract
We have shown that a hybrid motor consisting of proton-type Rhodobacter sphaeroides MotA and sodium-type VIBRIO: alginolyticus PomB, MotX and MotY, can work as a sodium-driven motor in VIBRIO: cells. In this study, we tried to substitute the B subunits, which contain a putative ion-binding site in the transmembrane region. Rhodobacter sphaeroides MotB did not work with either MotA or PomA in Vibrio cells. Therefore, we constructed chimeric proteins (MomB), which had N-terminal MotB and C-terminal PomB. MomB proteins, with the entire transmembrane region derived from the H(+)-type MotB, gave rise to an Na(+) motor with MotA. The other two MomB proteins, in which the junction sites were within the transmembrane region, also formed Na(+) motors with PomA, but were changed for Na(+) or Li(+) specificity. These results show that the channel part consisting of the transmembrane regions from the A and B subunits can interchange Na(+)- and H(+)-type subunits and this can affect the ion specificity. This is the first report to have changed the specificity of the coupling ions in a bacterial flagellar motor.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Amino Acid Sequence
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Bacterial Proteins / chemistry
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Bacterial Proteins / genetics
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Bacterial Proteins / metabolism*
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Cations, Monovalent / metabolism
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Cations, Monovalent / pharmacology
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Flagella / drug effects
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Flagella / metabolism*
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Genotype
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Hydrogen / metabolism
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Hydrogen / pharmacology
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Lithium / metabolism
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Lithium / pharmacology
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Locomotion / drug effects
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Membrane Proteins / genetics
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Membrane Proteins / metabolism
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Molecular Motor Proteins / metabolism
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Molecular Sequence Data
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Mutation
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Protons
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Recombinant Fusion Proteins / chemistry
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Recombinant Fusion Proteins / genetics
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Recombinant Fusion Proteins / metabolism*
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Rhodobacter sphaeroides* / genetics
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Sequence Alignment
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Sodium / metabolism
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Sodium / pharmacology
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Sodium Channels / chemistry
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Sodium Channels / genetics
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Sodium Channels / metabolism*
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Substrate Specificity
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Vibrio / drug effects
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Vibrio / genetics
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Vibrio / metabolism*
Substances
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Bacterial Proteins
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Cations, Monovalent
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Membrane Proteins
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Molecular Motor Proteins
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MotA protein, Bacteria
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MotB protein, Bacteria
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PomA protein, Vibrio
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PomB protein, Vibrio
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Protons
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Recombinant Fusion Proteins
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Sodium Channels
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Hydrogen
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Lithium
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Sodium