A CANDIDA-ALBICANS CYCLIC-NUCLEOTIDE PHOSPHODIESTERASE - CLONING AND EXPRESSION IN SACCHAROMYCES-CEREVISIAE AND BIOCHEMICAL-CHARACTERIZATION OF THE RECOMBINANT ENZYME

We have cloned a Candida albicans gene, which encodes a cyclic nucleot ide phosphodiesterase (PDEase), by complementation in a Saccharomyces cerevisiae PDEase-deficient mutant. The deduced amino acid sequence is similar to that of the low-affinity PDEase of S. cerevisiae (PDE1) an d the cyclic nucleotide PDEase (PD) of Dictyostelium discoideum. Bioch emical analysis of recombinant protein produced in S. cerevisiae indic ated that the enzyme behaves as a PDE1 homologue: it hydrolyses bath c AMP (K-m = 0.49 mM) and cGMP (K-m = 0.25 mM), does not require divalen t cations for maximal activity and is only moderately inhibited by mil limolar concentrations of standard PDEase inhibitors. Based on these d ata, we designate the C. albicans we have cloned, PDE1. Low-stringency genomic Southern blots showed crosshybridization between C. albicans PDE1 and DNA from Candida stellatoidea, but not with DNA from S. cerev isiae or several closely related Candida species.