1. Dynamical simulations of virus wrapping and budding T. Ruiz-Herrero 1, M. F. Hagan 2, E. Velasco 1 1.Universidad Autónoma de Madrid, Madrid, Spain 2.Brandeis University, Waltham, MA, USA

2. INTRODUCTION Budding exiting the cell acquiring membrane coating Attachment to the cell membrane Wrapping Fusion of the final neck Budding steps T. RUIZ-HERRERO 1/13

3. COARSE GRAINING polar headHydrophilic tail T. RUIZ-HERRERO 2/13

4. MEMBRANE MODEL:cooke model V rep V bond V bend V atrr [Cooke et al, Phys. Rev. E, 72 (2205)] T. RUIZ-HERRERO 3/13

5. MEMBRANE MODEL CHARACTERISTICS ● Broad range of fluidity ● Easily tunable ● Good agreement with measurements: rigidity, diffusion, density ωCωC κ/ε0 κ/ε0 ωCωC A/σ 2 k B T/ε 0 =1.1 [from Cooke et al,Phys Rev E, 72 (2205)] Area per molecule Bending rigidity T. RUIZ-HERRERO 4/13

6. MEMBRANE PARTICLE INTERACTION AND SIMULATION CHARACTERISTICS s=R-σ/2 Simulation characteristics: Important parameters: Molecular dynamics simulation R NPT ensamble ε Langevin thermostat k B T/ε=1.1 ω c κ,ρ Andersen barostat P=0 Verlet algorithm s Membrane-particle interaction T. RUIZ-HERRERO 5/13

7. SIMULATIONS RESULTS: MAIN BEHAVIORS WRAPPING NON-WRAPPING T. RUIZ-HERRERO 6/13 MEMBRANE BREAKING

8. SYSTEM BEHAVIOR 1: NON-WRAPPING  /  0 =1e3  /  0=5e3  /  0=1e4  /  0=3e4 T. RUIZ-HERRERO 7/13

9. SYSTEM BEHAVIOR 2: WRAPPING  /  0=5e2  /  0=5e3  /  0=1.5e4  /  0=1.55e4  /  0=1.6e4  /  0=1.65e4 T. RUIZ-HERRERO 8/13

10. SYSTEM BEHAVIOR 3: MEMBRANE BREAKING  /  0=5.5e3  /  0=6e3  /  0=7e3  /  =7.5e3  /  0=9.5e3  /  0=1e4 T. RUIZ-HERRERO 9/13

11. PHASE DIAGRAMS ε/ε0ε/ε0 In general, good agreement between simulations and theory Subtle dependence on bending coefficient For small epsilons deviation from theory /ε0/ε0 R/σ=10 R/σ ε/ε0ε/ε0  /k B T=12.5 T. RUIZ-HERRERO 10/13

12. ELASTIC THEORY T. RUIZ-HERRERO 11/13

13. ENERGY MAPS AND BUDDING PATHWAYS Penetration[σ] θ[rad] ε/ε 0 =0.7 ε/ε 0 =0.9 ε/ε 0 =1.1 T. RUIZ-HERRERO 12/13

14. BUDDING DYNAMICS: TIME SCALES AND PENETRATION Penetration vs time steepness of the budding pathway ---> process speed strenght adhesion energy ---> maximum penetration T. RUIZ-HERRERO 13/13