Sequence of subunit a of the Na(+)-translocating F1F0-ATPase of Acetobacterium woodii: proposal for residues involved in Na+ binding.
Na+ transport through the F0 domain of Na(+)-F1F0-ATPases involves the combined action of subunits c and a but the residues involved in Na+ liganding in subunit a are unknown. As a first step towards the identification of these residues, we have cloned and sequenced the gene encoding subunit a of the Na(+)-F1F0-ATPase of Acetobacterium woodii. This is the second sequence available now for this subunit from Na(+)-F1F0-ATPases. A comparison of subunit a from Na(+)-F1F0-ATPases with those from H(+)-translocating enzymes unraveled structural similarity in a C-terminal segment including the ultimate and penultimate transmembrane helix. Seven residues are conserved in this region and, therefore, likely to be involved in Na+ liganding.
Institut für Mikrobiologie und Genetik der Georg-August-Universität Göttingen, Germany.
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D000251:Adenosine Triphosphatases / Q000235:genetics / Q000378:metabolism*; D000595:Amino Acid Sequence; D001665:Binding Sites; D001692:Biological Transport; D027682:Cation Transport Proteins; D006093:Gram-Positive Asporogenous Rods / Q000201:enzymology*; D008969:Molecular Sequence Data; D017433:Protein Structure, Secondary; D006180:Proton-Translocating ATPases / Q000235:genetics / Q000378:metabolism; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D012964:Sodium / Q000378:metabolism*
D027682:Cation Transport Proteins; D012964:Sodium; D000251:Adenosine Triphosphatases; C021838:sodium-translocating ATPase; D006180:Proton-Translocating ATPases