The b _arg36 contributes to efficient coupling in F₁F_O ATP synthase in Escherichia coli

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• 作者：Amanda K. Welch ; Shane B. Claggett and Brian D. Cain
• 关键词：F1FO ATP synthase ; b Subunits ; ATPase
• 刊名：Journal of Bioenergetics and Biomembranes
• 出版时间：February, 2008
• 出版年：2008
• 期刊代码：13_0145479X
• 类别：en
• 卷：40
• 期：1
• 页码：1-8
• 数据来源：sp

摘要

In Escherichia coli, the F₁F_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. F₁F_O ATP synthase complexes were more efficiently assembled and ATP driven proton pumping activity was improved. The evidence suggests that efficient coupling in F₁F_O ATP synthase is dependent upon a basic amino acid located at the base of the peripheral stalk.