Acid Proteinase Secreted by Candida Tropicalis: Functional Analysis of Preproregion Cleavages in C. Tropicalis and Saccharomyces Cerevisiae

Microbiology. 1996 Mar;142 ( Pt 3):493-503. doi: 10.1099/13500872-142-3-493.

Abstract

The 40 kDa secreted aspartyl proteinase (Sapt1) of Candida tropicalis is a pepsin-like enzyme encoded by the SAPT1 gene. According to the deduced amino acid sequence. Sapt1 has a putative preproregion of 60 amino acids preceding the mature enzyme. Maturation and processing of Sapt1 was analysed in C. tropicalis and Saccharomyces cerevisiae strains expressing wild-type or mutated forms of SAPT1. In S. cerevisiae, the glycosylated 46 kDa proenzyme was converted to the mature 40 kDa form of Sapt1 by KEX2-dependent proteolytic cleavage following the Lys59-Arg60 sequence. The replacement of Lys59-Arg60 by Lys59-Gly60 revealed that the precursor can be processed by an autocatalytic cleavage. This alternative processing pathway to produce mature Sapt1 is less efficient than the Kex2-mediated pathway. Finally, it was shown that in C. tropicalis and S. cerevisiae the removal of the proregion was a prerequisite for the secretion of Sapt1.

MeSH terms

  • Candida / enzymology*
  • Endopeptidases / genetics
  • Endopeptidases / metabolism*
  • Enzyme Precursors / genetics
  • Enzyme Precursors / metabolism*
  • Mutagenesis, Site-Directed
  • Plasmids / genetics
  • Saccharomyces cerevisiae / enzymology*

Substances

  • Enzyme Precursors
  • Endopeptidases