Histidinol dehydrogenase, HisD, E.C 18.104.22.168. Histidinol dehydrogenase catalyzes the last two steps in the L-histidine biosynthesis pathway, which is conserved in bacteria, archaea, fungi, and plants. These last two steps are (i) the NAD-dependent oxidation of L-histidinol to L-histidinaldehyde, and (ii) the NAD-dependent oxidation of L-histidinaldehyde to L-histidine. In most fungi and in the unicellular choanoflagellate Monosiga bevicollis, the HisD domain is fused with units that catalyze the second and third biosynthesis steps in this same pathway.
Structure:1KAE: L-Histidinol dehydrogenase monomer from Escherichia coli; the catalytic residues line up with a water molecule and the substrate, which in turn participates in the octahedral coordination of the zinc ion. - View structure with Cn3D