Antifungal activity of synthetic 15-mer peptides based on the Rs-AFP2 (Raphanus sativus antifungal protein 2) sequence

摘要: Plant defensins are a class of cysteine-rich peptides which several members have been shown to be potent inhibitors fungal growth. A series overlapping 15-mer based on the amino acid sequence radish antifungal protein Rs-AFP2 synthesized. Peptides 6, 7, 8 and 9, comprising region from cysteine 27 47 showed substantial activity against species (minimal inhibitory concentrations 30-60 micrograms/mL), but no towards bacteria (except peptide 6 at 100 micrograms/mL). The active were sensitive presence cations in medium composition pH medium. When present subinhibitory concentration (20 1, 10 potentiated 2.3-fold 2.8-fold. By mapping characteristics structure as determined by nuclear magnetic resonance, appears involve beta-strands 2 3 combination with loop connecting those strands. cyclized synthetic mimic loop, 36 45, was activity. Substitution tyrosine 38 alanine cyclic substantially reduced activity, indicating importance this residue for demonstrated carrier mutational analysis.