Glutamate residues at positions 219 and 252 in the a-subunit of the Escherichia coli ATP synthase are not functionally equivalent.
The role of glutamate-219 in the a-subunit of the Escherichia coli F0F1-ATPase was examined using site-directed mutagenesis. The replacement of Glu-219 by lysine, alanine or glycine resulted in a partially functional F0F1-ATPase. Combining any of these mutations with the substitution of glutamate for Gln-252 did not result in any increase in function. These findings rule out a proposal that glutamate at position 252 can functionally replace glutamate at position 219 [S.B. Vik, B.J. Antonio, J. Biol. Chem. 269 (1994) 30364-30369]. All the single and double mutants grew better at 25 degrees C than at 37 degrees C, suggesting a role for Glu-219 in maintaining the structure of the F0.
Hatch
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LP
Membrane Biochemistry Group, Division of Biochemistry and Molecular Biology, John Curtin School of Medical Research, Australian National University, P.O. Box 334, Canberra, ACT 0200, Australia. lundall.hatch.anu.edu.au
Cox
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Howitt
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D002462:Cell Membrane / Q000201:enzymology; D003198:Computer Simulation; D004926:Escherichia coli / Q000201:enzymology* / Q000235:genetics; D018698:Glutamic Acid / Q000032:analysis* / Q000378:metabolism; D016297:Mutagenesis, Site-Directed; D006180:Proton-Translocating ATPases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism
D018698:Glutamic Acid; D006180:Proton-Translocating ATPases