Psd2 pea defensin shows a preference for mimetic membrane rafts enriched with glucosylceramide and ergosterol

Publication date: Available online 10 January 2019Source: Biochimica et Biophysica Acta (BBA) - BiomembranesAuthor(s): Virginia Sara Grancieri do Amaral, Caroline Mota Fernandes, Mário R. Felício, Aline Sol Valle, Paula G. Quintana, Caroline Correa de Almeida, Eliana Barreto-Bergter, Sónia Gonçalves, Nuno C. Santos, Eleonora KurtenbachAbstractPsd2 is a pea defensin with 47 amino acid residues that inhibits the growth of fungal species by an uncharacterized mechanism. In this work, Psd2 interactions with model membranes mimicking the lipid compositions of different organisms were evaluated. Protein-lipid overlay assays indicated that Psd2 recognizes Fusarium solani glucosylceramide (GlcCerF.solani) and ergosterol (Erg) in addition to phosphatidylcholine (POPC) and some phosphatidylinositol species, such as PtdIns (3)P, (5)P and (3,5)P2, suggesting that these lipids may play important roles as Psd2 targets. Assays using lipid vesicles were also performed to study the behaviour and dynamics that occur after peptide-membrane interactions. Surface plasmon resonance analysis showed that Psd2 has a higher affinity for pure POPC and POPC-based vesicles containing GlcCer and Erg at a 70:30 proportion than for vesicles containing cholesterol (Chol). Partition experiments by fluorescence spectroscopy showed a decrease in Trp42 quantum yield of Psd2 in the presence of GlcCerF.solani and Erg, individually or in simultaneously enriched membranes. The partition coefficient (Kp) obtained...
Source: Biochimica et Biophysica Acta (BBA) Biomembranes - Category: Biochemistry Source Type: research