SEQUENCE AND EXPRESSION OF AN EISENIA-FETIDA-DERIVED CDNA CLONE THAT ENCODES THE 40-KDA FETIDIN ANTIBACTERIAL PROTEIN

Fetidins are 40-kDa and 45-kDa hemolytic and antibacterial glycoprotei ns present in the coelomic fluid of the earthworm Eisenia fetida andre i. By screening a cDNA library with a polyclonal anti-fetidin serum, w e have cloned a cDNA that encoded the 40-kDa fetidin. The clone contai ns an insert of 1.44 kb encoding a protein of 34 kDa, which correspond s to the size of deglycosylated fetidins. The recombinant protein inhi bits Bacillus megaterium growth. Restriction fragment polymorphisms we re observed on Southern blots and correspond to a known protein polymo rphism, The sequence of the cDNA contains a peroxidase signature and f etidins from earthworm coelomic fluid have peroxidase activity. The 40 -kDa and 45-kDa fetidins therefore represent two related polymorphic d efence factors in invertebrates.