UNIVERSITY OF BUCHAREST
FACULTY OF PHYSICS

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2024-11-23 18:24
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Conference: Bucharest University Faculty of Physics 2014 Meeting


Section: Biophysics; Medical Physics


Title:
Interaction of the antimicrobial peptides with lipid membrane


Authors:
B. MOGOS(1), Mihaela BACALUM(2), Doina GAZDARU(1)


Affiliation:
1) Faculty of Physics, University of Bucharest

2) Horia Hulubei” National

Institute for Research and Development in Physics and Nuclear

Engineering,Magurele-Ilfov,Romania


Mogos Bogdan, Doina Gazdaru :Department of Electricity and Solid State and

Biophysics, Faculty of Physics, University of Bucharest,

Magurele-Ilfov,Romania


E-mail
mogosh.bogdan@gmail.com


Keywords:
De novo antimicrobial peptides, melitin, fluorescence quenching.


Abstract:
A study of de novo antimicrobial peptides interaction with lipid membranes Introduction: Antimicrobial peptides (AMPs) are small peptides synthesized by different living organisms as an ancient innate defense mechanism against a variety of pathogens (bacteria, viruses, fungi). Due to their structural characteristics, AMPs exhibit a high selectivity towards bacteria and can be seen as an alternative to antibiotics. De novo peptides, with enhanced activity are generated using computational chemistry. It is really important to characterize these peptides and understand the mechanism by which they are interacting with the biological membranes. The aim of this study is to evaluate how 2 de novo designed antimicrobial peptides are interacting with lipid membranes similar with the ones of bacteria or mammals. Material and Methods: The 2 peptides have the following sequence: RRWWRHWRR (P1) and RRWWHWWRR (P7). Melitin (Mel), a well studied hemolytic and toxic AMP, was used as control. Membrane interaction was observed using fluorescence techniques: the blue shift of W emission and acrylamide quenching of W emission. Two types of SUVs (small unilamellar liposomes) were used: prepared from DOPC to mimic the mammalian membrane, or from a mixture of DOPC(85 %)/DPPG(15 %) to mimic the bacterial membrane Results: First we observed the new peptides exhibit smaller blue shift compared with Mel when are in put together with liposomes. Also tryptophan residues of the new peptides were less quenched compared with Mel when were inserted into the membrane of the SUVs. Conclusion: The new peptides do not insert into the lipid membrane, but are only adsorbed onto the surface of the membrane.