Mechanism of structural transformations induced by antimicrobial peptides in lipid membranes
| Autor: | K. Lam, Alan J. Waring, Ka Yee C. Lee, Ting Ann Siaw, Hao Wang, James T. Kindt, Matthew George Chapman |
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| Rok vydání: | 2012 |
| Předmět: |
Pore formation
Membrane permeability Molecular Sequence Data Biophysics Phospholipid Molecular dynamics Model lipid bilayer 010402 general chemistry 01 natural sciences Biochemistry Protein Structure Secondary Membrane Lipids Atomic force microscopy 03 medical and health sciences chemistry.chemical_compound Lipid bilayer phase behavior Lipid bilayer 030304 developmental biology Membrane disruption mechanism 0303 health sciences Molecular Structure Bilayer Cell Membrane Biological membrane Cell Biology Protegrin-1 0104 chemical sciences Crystallography Membrane chemistry Dimyristoylphosphatidylcholine Antimicrobial Cationic Peptides |
| Zdroj: | Biochimica et Biophysica Acta (BBA) - Biomembranes. 1818:194-204 |
| ISSN: | 0005-2736 |
| Popis: | It has long been suggested that pore formation is responsible for the increase in membrane permeability by antimicrobial peptides (AMPs). To better understand the mechanism of AMP activity, the disruption of model membrane by protegrin-1 (PG-1), a cationic antimicrobial peptide, was studied using atomic force microscopy. We present here the direct visualization of the full range of structural transformations in supported lipid bilayer patches induced by PG-1 on zwitterionic 1,2-dimyristoyl-snglycero-phospho-choline (DMPC) membranes. When PG-1 is added to DMPC, the peptide first induces edge instability at low concentrations, then pore-like surface defects at intermediate concentrations, and finally wormlike structures with a specific length scale at high concentrations. The formation of these structures can be understood using a mesophase framework of a binary mixture of lipids and peptides, where PG-1 acts as a line-active agent. Atomistic molecular dynamics simulations on lipid bilayer ribbons with PG-1 molecules placed at the edge or interior positions are carried out to calculate the effect of PG-1 in reducing line tension. Further investigation of the placement of PG-1 and its association with defects in the bilayer is carried out using unbiased assembly of a PG-1 containing bilayer from a random mixture of PG-1, DMPC, and water. A generalized model of AMP induced structural transformations is also presented in this work. This article is part of a Special Issue entitled: Membrane protein structure and function. |
| Databáze: | OpenAIRE |
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