human O-GlcNAc transferase

MD trajectory. The coordinates of the OGT?UDP?peptide complex (PDB 3PE4) were optimized in the Protein Preparation Wizard (Schrodinger 2009) where hydrogens were added; water molecules, UDP and peptide were stripped; and the structure was minimized using the OPLS2001 forcefield. The 1-?m simulation used the CHARM27 forcefield46, and the simple point charge model for water47. The CHARM27 forcefield was applied to the system using the VIPARR utility. The default Desmond relaxation was performed before simulation, and molecular dynamics were run at constant temperature (300?K) and pressure (1?bar). The simulation was performed by using the program Desmond, version 2.2.9.1.030 compiled by SBGrid on an optimized 64-node Linux-based InfiniBand cluster and took 75?days to complete. Molecular dynamics trajectories were processed and animated with VMD48.