A MOLECULAR-DYNAMICS STUDY OF GLUTATHIONE-REDUCTASE

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.