A tandem pair of Leishmania donovani cation transporting ATPase genes encode isoforms that are differentially expressed.

The second gene (ATPase 1b) of a tandem pair of cation transporting ATPases from Leishmania donovani was cloned and sequenced. The sequence of this gene was very similar to its upstream neighbor (ATPase 1a). Both genes contained a 2922 base open reading frame capable of encoding a protein of 974 amino acids. The genes differed at 34 nucleotide base positions, predicting 20 amino acid differences between the two peptides. These changes were clustered at the carboxy terminus with 15 changes occurring in the COOH-terminal 37 amino acids. However, these changes did not alter the highly charged nature of the carboxy terminus observed in ATPase 1a. The sequence was also conserved for 73 bases upstream of ATPase 1a and 1b but downstream conservation was limited to 15 bases beyond the termination codon. RNA from ATPase 1a was 5.2 kb and was present in both developmental forms of Leishmania. By contrast the ATPase 1b gene expressed a 5.75 kb transcript which was much more abundant in the amastigote form of Leishmania than in the promastigote form.