Refined crystal structure of lipoamide dehydrogenase from Azotobacter vinelandii at 2.2 Å resolution: A comparison with the structure of glutathione reductase

The structure of lipoamide dehydrogenase from Azotobacter vinelandii has been refined by the molecular dynamics technique to an R-factor of 19.8% at 2.2 Å resolution. In the final model, the root-mean-square deviation from ideality is 0.02 Å for bond lengths and 3.2 ° for bond angles. The asymmetric unit comprises two subunits, each consisting of 466 amino acid residues and the prosthetic group FAD, plus 512 solvent molecules. The last ten amino acid residues of both chains are not visible in the electron density distribution and they are probably disordered. The operation required to superimpose the two chains forming the dimer is a rotation of exactly 180 ° with no translation component. The final model shows the two independently refined subunits to be very similar, except for six loops located at the surface of the molecul