Identification of Cecropin A Proteolytic Cleavage Sites Resulting from Aspergillus flavus Extracellular Protease(s)

• Published in: Journal of agricultural and food chemistry 1998-12, Vol.46 (12), p.5324-5327
• Main Authors: Bland, John M, De Lucca, Anthony J
• Format: Article
• Language: English
• Subjects: amino acid sequences; antifungal properties; Aspergillus flavus; Biological and medical sciences; Chemical control; conidia; Control; Fundamental and applied biological sciences. Psychology; Fungal plant pathogens; Microbiology; Mycology; nongerminating conidia; Pathogenicity, host-agent relations, miscellaneous strains, epidemiology; peptides; Phytopathology. Animal pests. Plant and forest protection; proteinases; proteolysis; spore germination
• ISSN: 0021-8561; 1520-5118
• DOI: 10.1021/jf980638i

Cecropin A (CA) has wide-spectrum antifungal properties except for the nongerminated conidial form of Aspergillus spp. A possible reason for this difference in activity has been explored. This study demonstrated that CA was being degraded enzymatically by proteases present in the culture supernatant. As a first step in the characterization of the type of protease responsible for the degradation of CA and for the prevention of degradation of gene-encoded antimicrobial peptides based on CA, the amino acids surrounding the cleavage sites were determined. On the basis of the molecular weights of the fragments, the cleavage sites were determined to be near the N terminus of the peptide at the Lys3−Leu4, Phe5−Lys6, and Lys7−Ile8 bonds. Keywords: Cecropin; Aspergillus flavus; protease; antifungal; reversed-phase high-performance liquid chromatography; electrospray mass spectrometry