Cloning and molecular analysis of the plasma membrane Ca2+-ATPase gene in Paramecium tetraurelia

We have determined the DNA sequence of the gene encoding the protein of the plasma membrane Ca2+-ATPase in Paramecium tetraurelia. The predicted amino acid sequence of the plasma membrane Ca2+-ATPase shows homology to conserved regions of known plasma membrane Ca2+-ATPases and contains the known binding sites for ATP (FITC), acylphosphate formation, and calmodulin, as well as the ''hinge'' region: all characteristics common to plasma membrane Ca2+-ATPases. The deduced molecular weight for this sequence is 131 kDa. The elucidation of this gene will assist in the studies of the mechanisms by which this excitable cell removes calcium entering through voltage gated calcium channels and the pump functions in chemosensory signal transduction.