Interaction between antimicrobial peptides and model membranes containing different lipid domains

• Grant number: 13/00473-6
• Support type: Scholarships abroad - Research Internship - Doctorate
• Effective date (Start): June 01, 2013
• Effective date (End): May 31, 2014
• Field of knowledge: Physical Sciences and Mathematics - Physics - Condensed Matter Physics
• Principal researcher: Maria Teresa Moura Lamy
• Grantee: Thais Azevedo Enoki
• Supervisor abroad: Gerald William Feigenson
• Home Institution: Instituto de Física (IF). Universidade de São Paulo (USP). São Paulo , SP, Brazil
• Research place: Cornell University, United States
• Associated to the scholarship: 10/11671-5 - Interaction of antimicrobial peptides with model membranes., BP.DR

Abstract

The present Project complements the PhD Project (FAPESP 2010/11671-5), extending it to the study of the interaction of antimicrobial peptides with more complex model membranes, those which contain lipid domains, sometimes called "rafts". This is in line with the presence of non-uniform mixing of lipids in biological membranes. The functional lipid raft was found to be related to the cell shape, and also supposed to be involved in important cell functions, like signaling, membrane transport, and protein sorting. The research group of Prof. Gerald Feigenson of Cornell University has given important contributions to the study of model membranes containing different lipid domains. They studied these systems using theoretical models and experimental techniques, including Fluorescence Spectroscopy, Electron Spin Resonance, Optical and Fluorescence Microscopy and Fluorescence Correlation Spectroscopy. This Project proposes the structural study of the interaction between antimicrobial peptides (AMPs) and model membranes which present complex lipid domains. The antimicrobial peptides to be investigated are those studied in the current PhD Project (FAPESP 2010/11671-5): Gomesin (Gm), which is an AMP isolated from the Brazilian spider Acanthoscurria gomesina, and its less toxic linear analogue [Ser2,6,11,15]-Gm (GmL), in which cysteine residues were replaced by serine ones, Hylin a1 (Hya1), an AMP isolated from the skin secretion of the frog Hypsiboas albopunctatus, and its analogues (K-Hya1 and D-Hya1), where lysine or aspartic acid was inserted in the first position, and a leucine was replaced by tryptophan at the 6th position to produce fluorescent peptides. Hence, we aim to put together the AMPs which are our object of study with the expertise of Prof. Feigenson group, studying the interaction of these peptides with complex model membrane systems, the latter closely mimicking biological membranes. We will investigate structural alterations caused by those peptides on the membrane, like segregation of lipid components, modification of the existing lipid rafts, changes on the boundary defects between lipid domains. Therefore, this proposal may help to understand the mechanism of action of AMPs, and perhaps create new analogs with reduced hemolytic effect and increased antimicrobial activity. (AU)

Scientific publications

(References retrieved automatically from Web of Science and SciELO through information on FAPESP grants and their corresponding numbers as mentioned in the publications by the authors)

ENOKI, THAIS A.; HEBERLE, FREDERICK A.; FEIGENSON, GERALD W. FRET Detects the Size of Nanodomains for Coexisting Liquid-Disordered and Liquid-Ordered Phases. BIOPHYSICAL JOURNAL, v. 114, n. 8, p. 1921-1935, APR 24 2018. Web of Science Citations: 5.