Manipulating the length of the b subunit F1 binding domain in F1F0 ATP synthase from Escherichia coli

• Published in: Journal of bioenergetics and biomembranes Vol. 37; no. 2; pp. 67 - 74
• Main Authors: Bhatt, Deepa, Cole, Stephanie P, Grabar, Tammy Bohannon, Claggett, Shane B, Cain, Brian D
• Format: Journal Article
• Language: English
• Published: United States Springer Nature B.V 01-04-2005
• Subjects: Amino Acid Sequence; Amino acids; ATP; Base Sequence; Binding Sites; Biochemistry; E coli; Escherichia coli - enzymology; Escherichia coli Proteins - chemistry; Escherichia coli Proteins - genetics; Escherichia coli Proteins - metabolism; Mitochondrial Proton-Translocating ATPases - chemistry; Mitochondrial Proton-Translocating ATPases - genetics; Mitochondrial Proton-Translocating ATPases - metabolism; Molecular Sequence Data; Mutagenesis, Insertional; Mutagenesis, Site-Directed; Mutation; Protein Conformation; Protein Subunits - chemistry; Protein Subunits - metabolism; Sequence Deletion
• ISSN: 0145-479X; 1573-6881
• DOI: 10.1007/s10863-005-4129-7

The peripheral stalk of F(1)F(0) ATP synthase is composed of a parallel homodimer of b subunits that extends across the cytoplasmic membrane in F(0) to the top of the F(1) sector. The stalk serves as the stator necessary for holding F(1) against movement of the rotor. A series of insertions and deletions have been engineered into the hydrophilic domain that interacts with F(1). Only the hydrophobic segment from val-121 to ala-132 and the extreme carboxyl terminus proved to be highly sensitive to mutation. Deletions in either site apparently abolished enzyme function as a result of defects is assembly of the F(1)F(0) complex. Other mutations manipulating the length of the sequence between these two areas had only limited effects on enzyme function. Expression of a b subunit with insertions with as few as two amino acids into the hydrophobic segment also resulted in loss of F(1)F(0) ATP synthase. However, a fully defective b subunit with seven additional amino acids could be stabilized in a heterodimeric peripheral stalk within a functional F(1)F(0) complex by a normal b subunit.