Evaluation of the membrane lipid selectivity of the pea defensin Psd1

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• 作者：Só ; nia Gonç ; alves^a ; Alexandre Teixeira^a ; Joã ; o Abade^a ; Luciano Neves de Medeiros^b ; ^c ; Eleonora Kurtenbach^b ; ^c ; Nuno C. Santos^a ; ^{nsantos@fm.ul.pt}
• 关键词：Psd1 ; Antimicrobial peptide ; Defensin ; Glycosphingolipids ; Ergosterol ; Fluorescence spectroscopy
• 刊名：Biochimica et Biophysica Acta (BBA)/Biomembranes
• 出版年：2012
• 期刊代码：14_00052736
• 类别：bio
• 出版时间：May, 2012
• 卷：1818
• 期：5
• 页码：1420-1426
• 文件大小：779 K

摘要

Psd1, a 46 amino acid residues defensin isolated from the pea Pisum sativum seeds, exhibits anti-fungal activity by a poorly understood mechanism of action. In this work, the interaction of Psd1 with biomembrane model systems of different lipid compositions was assessed by fluorescence spectroscopy. Partition studies showed a marked lipid selectivity of this antimicrobial peptide (AMP) toward lipid membranes containing ergosterol (the main sterol in fungal membranes) or specific glycosphingolipid components, with partition coefficients (K_p) reaching uncommonly high values of 10⁶. By the opposite, Psd1 does not partition to cholesterol-enriched lipid bilayers, such as mammalian cell membranes. The Psd1 mutants His36Lys and Gly12Glu present a membrane affinity loss relative to the wild type. Fluorescence quenching data obtained using acrylamide and membrane probes further clarify the mechanism of action of this peptide at the molecular level, pointing out the potential therapeutic use of Psd1 as a natural antimycotic agent.