Abstract.
Ligand-receptor molecular dynamics simulations (MDS) were carried out
for a set of hydrazides bound to the enoyl-acp reductase from M. tuberculosis,
InhA (PDB entry code 1zid). The hypothesized active conformations resulting
from a previous receptor-independent (RI) 4D-QSAR analysis and related
optimum model/alignment were used in this study. The molecular dynamics
simulations (MDS) protocol employed 500000 steps for each ligand-receptor
complex, the step size was 0.001 ps (1 fs), and the simulation temperature
was 310 K, the same temperature used in the biological assay. An output
trajectory file was saved every 20 simulation steps, resulting in 25,000
conformations. The hydration shell model was used to calculate the solvation
energy of the lowest-energy conformation obtained from each MDS. Structural
parameters as well as binding energy contributions were considered in this
analysis. The thermodynamic descriptors ELE1,4,
ELtors, ELvdW,
ELel, and ELel+Hb
appear to be more relevant to the biological activity. These findings can
be meaningful for developing QSAR studies and for designing new antituberculosis
agents.
Keywords.
Hydrazides; Enoyl-acp Reductase; Molecular Dynamics Simulations; Structure-Based
Design; Tuberculosis.
Keywords Plus.