The barg36 contributes to efficient coupling in F1FO ATP synthase in Escherichia coli

• Published in: Journal of bioenergetics and biomembranes Vol. 40; no. 1; pp. 1 - 8
• Main Authors: Welch, Amanda K., Claggett, Shane B., Cain, Brian D.
• Format: Journal Article
• Language: English
• Published: Boston Springer US 2008
• Subjects: Animal Anatomy; Animal Biochemistry; Biochemistry; Bioorganic Chemistry; Chemistry; Chemistry and Materials Science; Histology; Morphology; Organic Chemistry; ATP synthase; F; Subunits; ATPase
• DOI: 10.1007/s10863-008-9124-3
• EISSN: 1573-6881
• ISSN: 0145-479X

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.