ABSTRACT
A novel antifungal peptide, PcAFP (6.48 kDa, pI 8.83 ), was obtained from the culture supernatant of the fungus Penicillium crustosum . The gene encoding the PcAFP peptide was isolated b ased on its homologue in Penicillium chrysogenum , PgAFP. PcAFP is a small, cystine-rich peptide, and th e mature peptide consists of 58 amino acid residues. The i mmature P. crustosum antifungal protein (AFP) showed 95.65% identity to the antifungal prote in of P. chrysogenum , while the mature peptide showed 98.28% identity with PgAFP. Molecular modeling of the tertiary structure of the mature peptide revealed details of the conserved stru cture of the AFPs, such as the ? -barrel motif stabilized by three disulfide bonds and the ? -core motif. Analysis of the extract by 16% tricine SD S- PAGE showed a 6.9 kDa peptide, which was close to the pr edicted molecular mass of the mature peptide of 6.48 kDa. Assays of antimicrobial activity , performed by broth microdilution using the crude extract obtained from the culture medium, showe d activity against Candida albicans . These results demonstrate the conservation of the PcAPF gene and the high level of identity with the PgAFP antifungal protein of P. chrysogenum . Given these structural and biochemical characteristics, PcAFP could be a potential candidate for future investigations that may aid in the development of new antifungal compounds.