title: Psd1 binding affinity toward fungal membrane components as assessed by SPR: The role of glucosylceramide in fungal recognition and entry.
abstract: Psd1 is a plant defensin that has antifungal activity against several pathogenic and nonpathogenic fungi. Previous analysis of Psd1 chemical shift perturbations by nuclear magnetic resonance (NMR) spectroscopy demonstrated that this defensin interacts with phospholipids and the sphingolipid glucosylceramide isolated from Fusarium solani (GlcCer(Fusarium solani)). In this study, these interactions were evaluated by real-time surface plasmon resonance (SPR) analysis. The data obtained demonstrated that Psd1 could bind more strongly to small unilamellar vesicles (SUV)-containing GlcCer(Fusarium solani) than to SUV that was composed of phosphatidylcholine (PC) alone or was enriched with GlcCer that had been isolated from soybeans. An increase in the SPR response after cholesterol or ergosterol incorporation in PC-SUV was detected; however, SUV composed of PC:Erg (7:3; molar:molar) became unstable in the presence of Psd1, suggesting membrane destabilization. We also observed a lack of Psd1 internalization in Candida albicans strains that were deficient in the glucosyl ceramide synthase gene. Together, these data indicate that GlcCer is essential for Psd1 anchoring in the fungal plasma membrane as well as internalization.
authors.affiliation: Programa de Biologia Molecular e Estrutural, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, 21941-902, Brasil; Instituto Nacional para Pesquisa Translacional em Saúde e Ambiente na Região Amazônica, Conselho Nacional de Desenvolvimento Científico e Tecnológico/MCT, Rio de Janeiro, RJ, 21941-902, Brasil.
authors.forename: Luciano Neves
authors.initials: LN
authors.lastname: de Medeiros
authors.forename: Tatiana
authors.initials: T
authors.lastname: Domitrovic
authors.forename: Paula Cavalcante
authors.initials: PC
authors.lastname: de Andrade
authors.forename: Jane
authors.initials: J
authors.lastname: Faria
authors.forename: Eliana Barreto
authors.initials: EB
authors.lastname: Bergter
authors.forename: Gilberto
authors.initials: G
authors.lastname: Weissmüller
authors.forename: Eleonora
authors.initials: E
authors.lastname: Kurtenbach
mesh_terms: D002176:Candida albicans / Q000187:drug effects / Q000254:growth & development / Q000502:physiology*; D023082:Defensins / Q000378:metabolism* / Q000494:pharmacology; D004705:Endocytosis / Q000187:drug effects; D005963:Glucosylceramides / Q000378:metabolism*; D007700:Kinetics; D008081:Liposomes / Q000378:metabolism*; D008826:Microbial Sensitivity Tests; D018613:Microscopy, Confocal; D010713:Phosphatidylcholines / Q000378:metabolism; D010940:Plant Proteins / Q000378:metabolism* / Q000494:pharmacology; D020349:Surface Plasmon Resonance
chemical_list: D023082:Defensins; D005963:Glucosylceramides; D008081:Liposomes; D010713:Phosphatidylcholines; D010940:Plant Proteins; C410643:defensin 1, Pisum sativum
keywords: Pisum sativum defensin 1 (Psd1); antimicrobial peptides; glucosylceramide; plant defensins; surface plasmon resonance