Energy complexes are apparently associated with the switch-motor complex of bacterial flagella.
Recently, the switch-motor complex of bacterial flagella was found to be associated with a number of non-flagellar proteins, which, in spite of not being known as belonging to the chemotaxis system, affect the function of the flagella. The observation that one of these proteins, fumarate reductase, is essentially involved in electron transport under anaerobic conditions raised the question of whether other energy-linked enzymes are associated with the switch-motor complex as well. Here, we identified two additional such enzymes in Escherichia coli. Employing fluorescence resonance energy transfer in vivo and pull-down assays invitro, we provided evidence for the interaction of F(0)F(1) ATP synthase via its β subunit with the flagellar switch protein FliG and for the interaction of NADH-ubiquinone oxidoreductase with FliG, FliM, and possibly FliN. Furthermore, we measured higher rates of ATP synthesis, ATP hydrolysis, and electron transport from NADH to oxygen in membrane areas adjacent to the flagellar motor than in other membrane areas. All these observations suggest the association of energy complexes with the flagellar switch-motor complex. Finding that deletion of the β subunit in vivo affected the direction of flagellar rotation and switching frequency further implied that the interaction of F(0)F(1) ATP synthase with FliG is important for the function of the switch of bacterial flagella.
Department of Biological Chemistry, The Weizmann Institute of Science, 76100 Rehovot, Israel.
Gabriel
G
Zarbiv
Hui
H
Li
Amnon
A
Wolf
Gary
G
Cecchini
S Roy
SR
Caplan
Victor
V
Sourjik
Michael
M
Eisenbach
D000255:Adenosine Triphosphate / Q000378:metabolism; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics; D042967:Electron Transport Complex I / Q000737:chemistry / Q000378:metabolism; D004926:Escherichia coli / Q000201:enzymology* / Q000378:metabolism; D029968:Escherichia coli Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D031541:Fluorescence Resonance Energy Transfer; D005812:Genes, Switch; D006868:Hydrolysis; D008958:Models, Molecular; D006180:Proton-Translocating ATPases / Q000737:chemistry / Q000378:metabolism; D013385:Succinate Dehydrogenase / Q000737:chemistry / Q000378:metabolism
D001426:Bacterial Proteins; D029968:Escherichia coli Proteins; C077389:FliN protein, Bacteria; C075660:Flig protein, Bacteria; C066821:FliM protein, Bacteria; D000255:Adenosine Triphosphate; D013385:Succinate Dehydrogenase; D006180:Proton-Translocating ATPases; D042967:Electron Transport Complex I