A GENE (SLEC) ENCODING A SPORE-CORTEX-LYTIC ENZYME FROM CLOSTRIDIUM-PERFRINGENS-S40 SPORES - CLONING, SEQUENCE-ANALYSIS AND MOLECULAR CHARACTERIZATION

Antiserum was raised against a 31 kDa spore-cortex-lytic enzyme, which is released during germination of Clostridium perfringens S40 spores. Western blotting of dormant spore and vegetative cell fractions separ ated by SDS-PACE indicated that the 31 kDa enzyme is spore-specific an d that the enzyme in the dormant spore exists as a 36 kDa protein whic h has no cortex-lytic activity. A gene encoding the 31 kDa enzyme, sle C, was cloned into Escherichia coil using a synthetic oligonucleotide as a hybridization probe and the nucleotide sequence of the entire gen e was determined. The N-terminal amino acid sequence of the 36 kDa pro tein was found in this reading frame, confirming that the 36 kDa prote in is a pro-form of the 31 kDa enzyme. the deduced amino acid sequence indicated that the 31 kDa enzyme is produced as a precursor, comprisi ng three portions; an N-terminal prepro-sequence (114 amino acid resid ues), a pro-sequence (35 amino acid residues) and a mature enzyme (289 amino acid residues). It is suggested that the 36 kDa pro-enzyme is n on-covalently attached to the exterior of the cortex layer, and that t he pro-form is processed to release the active enzyme during germinati on.