Conservation of complete trimethylation of lysine-43 in the rotor ring of c-subunits of metazoan adenosine triphosphate (ATP) synthases.
Bottom Line: In the twenty-nine metazoan species that have been examined, the complete methylation of lysine-43 is conserved, and it is likely to be conserved throughout the more than two million extant metazoan species.In unicellular eukaryotes and prokaryotes, when the lysine is conserved it is unmethylated, and the stoichiometries of c-subunits vary from 9-15.One possible role for the trimethylated residue is to provide a site for the specific binding of cardiolipin, an essential component of ATP synthases in mitochondria.
Affiliation: From the ‡Mitochondrial Biology Unit, Medical Research Council, Hills Road, Cambridge, CB2 0XY, United Kingdom and.Show MeSH
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Mentions: Lysine-43 is trimethylated completely in the fifteen vertebrate c-subunits of F-ATPases that were studied. The vertebrate species include representatives of all classes (mammals, reptiles, birds, amphibians, ray-finned, and cartilaginous fishes), except for the sarcopterygii, or lobe-finned fishes (see Fig. 7). With the exception of the c-subunit from an opossum, and an elephant the known sequences of vertebrate c-subunits are identical (Fig. 3); in the opossum sequence the two conservative point substitutions, Ile2Val and Met73Leu, are found at and near the N- and C termini of protein, respectively, as is Ile2Val in the elephant. Therefore, it is reasonable to conclude from the identity or near identity of the sequences of c-subunits that all of the vertebrate F-ATPases will not only contain c8-rings, but that on the basis of the current investigations, that all vertebrate c-proteins will contain a fully trimethylated lysine-43. It has been estimated that there are ∼50,000 vertebrate species on Earth today (34).
Affiliation: From the ‡Mitochondrial Biology Unit, Medical Research Council, Hills Road, Cambridge, CB2 0XY, United Kingdom and.