title: The b (arg36) contributes to efficient coupling in F(1)F (O) ATP synthase in Escherichia coli.
abstract: In Escherichia coli, the F(1)F(O) ATP synthase b subunits house a conserved arginine in the tether domain at position 36 where the subunit emerges from the membrane. Previous experiments showed that substitution of isoleucine or glutamate result in a loss of enzyme activity. Double mutants have been constructed in an attempt to achieve an intragenic suppressor of the b (arg36-->ile) and the b (arg36-->glu) mutations. The b (arg36-->ile) mutation could not be suppressed. In contrast, the phenotypic defect resulting from the b (arg36-->glu) mutation was largely suppressed in the b (arg36-->glu,glu39-->arg) double mutant. E. coli expressing the b (arg36-->glu,glu39-->arg) subunit grew well on succinate-based medium. F(1)F(O) ATP synthase complexes were more efficiently assembled and ATP driven proton pumping activity was improved. The evidence suggests that efficient coupling in F(1)F(O) ATP synthase is dependent upon a basic amino acid located at the base of the peripheral stalk.
authors.affiliation: Department of Biochemistry, University of Florida, 1600 SW Archer Rd., P.O. Box 100245, Gainesville, FL 32610, USA.
authors.forename: Amanda K
authors.initials: AK
authors.lastname: Welch
authors.forename: Shane B
authors.initials: SB
authors.lastname: Claggett
authors.forename: Brian D
authors.initials: BD
authors.lastname: Cain
mesh_terms: D019943:Amino Acid Substitution; D001120:Arginine / Q000235:genetics / Q000378:metabolism; D025243:Bacterial Proton-Translocating ATPases / Q000235:genetics / Q000378:metabolism*; D020134:Catalytic Domain / Q000502:physiology; D004926:Escherichia coli / Q000201:enzymology* / Q000235:genetics; D029968:Escherichia coli Proteins / Q000235:genetics / Q000378:metabolism*; D017434:Protein Structure, Tertiary / Q000502:physiology
chemical_list: D029968:Escherichia coli Proteins; D001120:Arginine; D025243:Bacterial Proton-Translocating ATPases