3D-model of Kluyveromyces lactis glutathione reductase performed with PyMOL Molecular Viewer http://pymol.sourceforge.net/ (A) Domains are marked in colours. Blue: dimerization domain. Yellow: NADPH binding domain. Red: FAD binding domain. The arrow points out the disulphide bridge that makes up the catalytic domain (B) Residues different from S. cerevisiae glutathione reductase are marked in blue, these differences do not affect significantly the overall structure of the protein.