Molecular evaluation of the plasma membrane proton pump from Aspergillus fumigatus

Antimicrob Agents Chemother. 2002 Mar;46(3):615-24. doi: 10.1128/aac.46.3.615-624.2002.

Abstract

The gene encoding the plasma membrane proton pump (H+ -ATPase) of Aspergillus fumigatus, PMA1, was characterized from A. fumigatus strain NIH 5233 and clinical isolate H11-20. An open reading frame of 3,109 nucleotides with two introns near the N terminus predicts a protein consisting of 989 amino acids with a molecular mass of approximately 108 kDa. The predicted A. fumigatus enzyme is 89 and 51% identical to H+ - ATPases of Aspergillus nidulans and Saccharomyces cerevisiae, respectively. The A. fumigatus PMA1 is a typical member of the P-type ATPase family that contains 10 predicted transmembrane segments and conserved sequence motifs TGES, CSDKTGT, MLTGD, and GDGVN within the catalytic region. The enzyme represents 2% of the total plasma membrane protein, and it is characteristically inhibited by orthovanadate, with a 50% inhibitory concentration of approximately 1.8 microM. H+ -ATPases from Aspergillus spp. contain a highly acidic insertion region of 60 amino acids between transmembrane segments 2 and 3, which was confirmed for the membrane-assembled enzyme with a peptide-derived antibody. An increasing A. fumigatus PMA1 copy number confers enhanced growth in low-pH medium, consistent with its role as a proton pump. These results provide support for the development of the A. fumigatus H+ -ATPase as a potential drug discovery target.

MeSH terms

  • Adenosine Triphosphatases / metabolism
  • Adenosine Triphosphate / metabolism
  • Amino Acid Sequence
  • Aspergillus fumigatus / enzymology*
  • Aspergillus fumigatus / genetics
  • Base Sequence
  • Blotting, Western
  • Cell Membrane / enzymology
  • Cloning, Molecular
  • DNA, Fungal / biosynthesis
  • DNA, Fungal / genetics
  • DNA, Fungal / isolation & purification
  • Molecular Sequence Data
  • Proton Pumps / genetics
  • Proton Pumps / metabolism*
  • Proton-Translocating ATPases / metabolism
  • RNA, Fungal / biosynthesis
  • RNA, Fungal / genetics
  • RNA, Fungal / isolation & purification
  • Reverse Transcriptase Polymerase Chain Reaction
  • Saccharomyces cerevisiae Proteins / metabolism

Substances

  • DNA, Fungal
  • Proton Pumps
  • RNA, Fungal
  • Saccharomyces cerevisiae Proteins
  • Adenosine Triphosphate
  • Adenosine Triphosphatases
  • PMA1 protein, S cerevisiae
  • Proton-Translocating ATPases