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Two overlapping genes in bovine mitochondrial DNA encode membrane components of ATP synthase.
Author(s) -
Fearnley I.M.,
Walker J.E.
Publication year - 1986
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.1002/j.1460-2075.1986.tb04456.x
Subject(s) - biology , atp synthase , mitochondrial dna , gene , atpase , biochemistry , homology (biology) , mitochondrion , inner mitochondrial membrane , dna , microbiology and biotechnology , enzyme , genetics
Two hydrophobic proteins have been purified to homogeneity from a mixture of about 13 proteins that are extracted from bovine mitochondria with a chloroform:methanol mixture. Sequence analysis shows that the smaller is a protein of 66 amino acids and is the product of a mitochondrial gene, A6L. The larger, a protein of 226 amino acids, is ATPase‐6, a membrane component of ATP synthase, also encoded in mitochondrial DNA. The protein sequences determined establish that the genes for the two proteins overlap by 40 bases and indicate that translation of the second gene, ATPase‐6, is initiated within the coding region of A6L. The A6L and the ATPase‐6 proteins have also been isolated from the ATP synthase complex and so appear to be bona fide components of the enzyme. The function of A6L is unknown. However, weak structural homology suggests a functional similarity to the yeast mitochondrial protein, aapI, which is required for assembly of the fungal ATP synthase complex. Homologies between ATPase‐6 and subunit a of the Escherichia coli ATP synthase complex indicate that the ATPase‐6 protein has a similar role in the mitochondrial complex to its bacterial counterpart, being essential for the formation of an active proton channel.