Isolation of genes encoding the Neurospora vacuolar ATPase. Analysis of vma-2 encoding the 57-kDa polypeptide and comparison to vma-1.
In partially purified preparations of the vacuolar ATPase from Neurospora crassa, the two most prominent components are polypeptides of Mr = 70,000 and 60,000. We previously reported the isolation of the gene vma-1, which encodes the Mr = 70,000 polypeptide, and presented evidence that the polypeptide contains the site of ATP hydrolysis (Bowman, E. J., Tenney, K., and Bowman, B. J. (1988) J. Biol. Chem. 263, 13994-14001). We now report the isolation of a gene (designated vma-2), that encodes the Mr = 60,000 polypeptide. Analysis of the DNA sequence shows that the polypeptide has 513 amino acids and a molecular mass of 56,808 daltons (and will thus be referred to as the 57-kDa polypeptide). It is fairly rich in polar amino acids and has no apparent membrane-spanning domains. The vma-2 gene contains five short introns (55-71 bases), all clustered in the 5' end of the coding region. The gene maps to the right arm of linkage group II, near 5 S RNA gene 3. Thus, it is unlinked to vma-1 and to other known ATPase genes in N. crassa. The 57-kDa polypeptide shows 25% amino acid sequence identity with the vma-1 gene product. It shows essentially the same degree of similarity (25-28%) to both the alpha and beta subunits of F0F1 ATPases. Analysis of specific regions of the 57-kDa polypeptide, however, suggests it may have a function like that of the alpha subunit in F0F1 ATPases. The data indicate that all four types of ATPase polypeptides have evolved from a common ancestor and that the vacuolar-type ATPases have a structure surprisingly similar to that of the F0F1 ATPases.
Bowman
B J
BJ
Department of Biology, Thimann Laboratories, University of California, Santa Cruz 95064.
Allen
R
R
Wechser
M A
MA
Bowman
E J
EJ
D000251:Adenosine Triphosphatases / Q000235:genetics*; D000595:Amino Acid Sequence; D001483:Base Sequence; D003001:Cloning, Molecular; D004262:DNA Restriction Enzymes; D004271:DNA, Fungal / Q000235:genetics / Q000302:isolation & purification*; D046911:Macromolecular Substances; D008969:Molecular Sequence Data; D008970:Molecular Weight; D009491:Neurospora / Q000235:genetics*; D009492:Neurospora crassa / Q000201:enzymology / Q000235:genetics*; D014617:Vacuoles / Q000201:enzymology*
D004271:DNA, Fungal; D046911:Macromolecular Substances; D004262:DNA Restriction Enzymes; D000251:Adenosine Triphosphatases