The radish defensins RsAFP1 and RsAFP2 act synergistically with caspofungin against Candida albicans biofilms

Publication date: January 2016 Source:Peptides, Volume 75 Author(s): Kim Vriens, Tanne L. Cools, Peta J. Harvey, David J. Craik, Annabel Braem, Jozef Vleugels, Barbara De Coninck, Bruno P.A. Cammue, Karin Thevissen The radish defensin RsAFP2 was previously characterized as a peptide with potent antifungal activity against several plant pathogenic fungi and human pathogens, including Candida albicans. RsAFP2 induces apoptosis and impairs the yeast-to-hypha transition in C. albicans. As the yeast-to-hypha transition is considered important for progression to mature biofilms, we analyzed the potential antibiofilm activity of recombinant (r)RsAFP2, heterologously expressed in Pichia pastoris, against C. albicans biofilms. We found that rRsAFP2 prevents C. albicans biofilm formation with a BIC-2 (i.e., the minimal rRsAFP2 concentration that inhibits biofilm formation by 50% as compared to control treatment) of 1.65 ± 0.40mg/mL. Moreover, biofilm-specific synergistic effects were observed between rRsAFP2 doses as low as 2.5μg/mL to 10μg/mL and the antimycotics caspofungin and amphotericin B, pointing to the potential of RsAFP2 as a novel antibiofilm compound. In addition, we characterized the solution structure of rRsAFP2 and compared it to that of RsAFP1, another defensin present in radish seeds. These peptides have similar amino acid sequences, except for two amino acids, but rRsAFP2 is more potent than RsAFP1 against planktonic and biofilm cultures. Inte...
Source: Peptides - Category: Biochemistry Source Type: research