Membrane Association, Electrostatic Sequestration, and Cytotoxicity of Gly-Leu-Rich Peptide Orthologs with Differing Functions
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- 作者：Damien Vanhoye ; Francine Bruston ; Shaharazade El Amri ; Ali Ladram ; Mohamed Amiche ; and Pierre Nicolas
- 刊名：Biochemistry
- 出版年：2004
- 出版时间：July 6, 2004
- 年：2004
- 卷：43
- 期：26
- 页码：8391 - 8409
- 全文大小：592K
- 年卷期：v.43,no.26(July 6, 2004)
- ISSN：1520-4995
文摘
The skins of closely related frog species produce Gly-Leu-rich peptide orthologs that havevery similar sequences, hydrophobicities, and amphipathicities but differ markedly in their net chargeand membrane-damaging properties. Cationic Gly-Leu-rich peptides are hemolytic and very potent againstmicroorganisms. Peptides with no net charge have only hemolytic activity. We have used ancestral proteinreconstruction and peptide analogue design to examine the roles of electrostatic and hydrophobic interactionsin the biological activity and mode of action of functionally divergent Gly-Leu-rich peptides. The structureand interaction of the peptides with anionic and zwitterionic model membranes were investigated bycircular dichroism with 2-dimyristoyl-sn-glycero-3-phosphatidylcholine or 1,2-dimyristoyl-sn-glycero-3-phosphatidylglycerol vesicles and surface plasmon resonance with immobilized bilayers. The results,combined with antimicrobial assays, the kinetics of bacterial killing, and membrane permeabilization assays,reveal that Gly, Val, Thr, and Ile can all be accommodated in an amphipathic 
helix when the helix isin a membrane environment. Binding to anionic and zwitterionic membranes fitted to a 2-stage interactionmodel (adsorption to the membrane followed by membrane insertion). The first step is governed byhydrophobic interactions between the nonpolar surface of the peptide helix and the membranes. The strongbinding of Gly-Leu-rich cationic peptides to anionic membranes is due to the second binding step andinvolves short-range Coulombic interactions that prolong the residence time of the membrane-insertedpeptide. The data demonstrate that evolution has positively selected charge-altering nucleotide substitutionsto generate an orthologous cationic variant of neutral hemolytic peptides that bind to and permeate bacterialcell membranes.
helix when the helix isin a membrane environment. Binding to anionic and zwitterionic membranes fitted to a 2-stage interactionmodel (adsorption to the membrane followed by membrane insertion). The first step is governed byhydrophobic interactions between the nonpolar surface of the peptide helix and the membranes. The strongbinding of Gly-Leu-rich cationic peptides to anionic membranes is due to the second binding step andinvolves short-range Coulombic interactions that prolong the residence time of the membrane-insertedpeptide. The data demonstrate that evolution has positively selected charge-altering nucleotide substitutionsto generate an orthologous cationic variant of neutral hemolytic peptides that bind to and permeate bacterialcell membranes.