Biophysical Society Thematic Meeting - October 13-15, 2015

Biophysics of Proteins at Surfaces: Assembly, Activation, Signaling

Poster Abstracts

37-POS Board 37 Pore Forming of Fragaceatoxin C into Membrane Studied by Coarse-grained Molecular Dynamics Simulations Khuong Truong 1,2,3 , Myunggi Yi 1,2,3 . 2 Center of Marine-integrated Biomedical Technology (BK21+), Pukyong National Uni, Busan, South Korea, 1 Interdisciplinary Program of Biomedical, Electrical & Mechanical Engineering, Pukyong National Uni, Busan, South Korea, 3 Marine Integrated Bionics Research Center, Pukyong National Uni, Busan, South Korea, 4 Department of Biomedical Engineering, Pukyong National Uni, Busan, South Korea. Pore-forming toxins (PFT) are water-soluble proteins. They have ability to self-assemble on the membrane. They form oligomeric transmembrane pores and this causes cell damage. Many studies have determined crystal structures of fragaceatoxin C, a PFT protein, at different states, monomer in water, monomer with lipid-bound, dimer on membrane and transmembrane pore. However, the mechanisms of lipid binding and conformational changes of fragaceatoxin C are still unclear. We carried out 4 coarse-grained molecular dynamics simulations of fragaceatoxin C in different states (monomer, dimer, oligomer (2 systems: pre-pore and pore)) with lipid bilayer. The bilayer was composed of a mixture of Sphingomyeline (SM) and DOPC lipid at molar ratio 1:1. Long time simulations were performed to observe self assembly of fragaceatoxin C. Including monomer binding to membrane, two monomers bound to membrane making dimer then forming oligomer (pre-pore) and finally pore forming into membrane. We will present these self assemblies and corresponding conformational changes. These simulations provide molecular insight into pore forming of PFT into membrane.

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