Conformational analysis of ERX-11

A Monte Carlo conformational search was performed using the torsional sampling method (MCMM) implemented in MacroModel (version 9.0, Schrödinger, New York, NY) with automatic setup options. The calculation was done with the maximum number of steps set to 5000 using 100 steps per rotatable bond and an energy cutoff of 21 kJ/mol above the global energy minimum. The searches were done using MM3 force field (chosen for its accuracy with organic molecules) combined with the GB/SA water solvation model with standard settings and the following cut-offs: van der Waals, 8.0 Å; electrostatic, 20.0 Å; and hydrogen bond, 4.0 Å. The observed conformations were minimized by 500 iterations of Polak-Ribiere Conjugate Gradient (PRCG) algorithm (a conjugate gradient minimization scheme that uses the Polak-Ribiere first derivative method with restarts every 3N iterations) (0.05 kJ/mol).