Copper- and zinc-containing superoxide dismutase and its gene from Candidaalbicans

Cytosolic copper- and zinc-containing superoxide dismutase was purified 136 -fold with an overall yield of 2.5% to apparent electrophoretic homogeneity from the dimorphic pathogenic fungus, Candida albicans. The molecular mass of the native enzyme was 39.4 kDa and the enzyme was composed of two ident ical subunits with a molecular mass of 19.6 kDa. The enzyme was stable in t he range of pH 3.0-9.0 and up to 55 degrees C. The ultraviolet-visible abso rption spectrum of the enzyme showed the absorption band of copper- and zin c-containing superoxide dismutase at 660 nm. The atomic absorption analysis revealed that the enzyme contained 0.87 g-atom of copper and 0.79 g-atom o f zinc per mole of subunit. The N-terminal amino acid sequence alignments u p to the 40th residue showed that copper- and zinc-containing superoxide di smutase from C. albicans has high similarity to other eukaryotic copper- an d zinc-containing superoxide dismutases. The sod1 encoding copper- and zinc -containing superoxide dismutase has been cloned using a polymerase chain r eaction fragment as a probe. Sequence analysis of the sod1 predicted a copp er- and zinc-containing superoxide dismutase that contains 154 amino acids with a molecular mass of 16 143 Da and displayed 79%, 69%, and 57% sequence identity to the homologues of Neurospora crassa, Saccharomyces cerevisiae, and bovine, respectively. The cloned sod1 contained an intron of 245 nucle otides, which was verified by reverse transcription-polymerase chain reacti on. (C) 1999 Elsevier Science B.V. All rights reserved.