A 200 ps molecular dynamics trajectory for the 8634 atoms correspondin
g to the enzyme glutathione reductase were calculated with the GROMOS
program. This enzyme is formed by two identical subunits, with 478 res
idues and a flavin-adenine dinucleotide (FAD) molecule each. Four regi
ons are well distinguished in its crystallographic structure, the dime
r interface, the FAD binding site, the active site and the crystal con
tact region. The analysis shows an equilibrated trajectory after 40 ps
. The r.m.s. difference between the X-ray structure and the conformati
on along the simulation is 2.4 Angstrom when considering the r.m.s. of
the whole molecule. The structure is locally well conserved. Values o
f r.m.s. lower than 2.0 Angstrom are found for all regions, with the e
xception of the crystal contact region. The results give evidence of a
fairly stable fold, especially for the catalytically active regions e
ven in the absence of explicit solvent collisions.