Photoisomerization Control Mechanisms in Protonated Schiff Bases

880-Pos Board B649 Dynamics of Amyloid Beta-Peptide (21-30) and its Iowa Mutation under Confinement and Crowding: A Molecular Dynamics Study Srinivasa Rao Jampani, Luis Cruz. Drexel University, Philadelphia, PA, USA. We present long time all-atommolecular dynamics simulations of the wild type (WT) and Iowa mutation of the amyloid b-protein (Ab) fragment (21-30) under confinement and crowding. To study the effects of confinement, we model the protein and solvent system to be confined inside spherical pores of varying sizes (12-24Å) composed of both, hydrophilic and hydrophobic walls. We discuss the dynamics of folding, and mechanisms of unfolding from a preformed b-hairpin under both confinement types by varying the size of the confined pore. Simulation results show that the dynamics of the WT and Iowa Ab(2130) in confinement (hydrophobic and hydrophilic) exhibit considerable variations from the corresponding bulk simulations. Also, the unfolding of preformed b-hairpin structures follow different mechanisms based on the pore type and closeness to the confined wall. These differences in mechanism are also reflected in the lifetimes of the preformed b-hairpin structures. We present effects of crowded environments on the dynamics of the WT Ab(21-30) by modeling the crowders as C70 and C60(OH)20 spherical fullerenes in explicit solvent. Results and detailed comparisons between the two systems will be presented.