title: Structural and mechanistic characteristics of dihydropteridine reductase: a member of the Tyr-(Xaa)3-Lys-containing family of reductases and dehydrogenases.
abstract: Dihydropteridine reductase (EC 1.6.99.7) is a member of the recently identified family of proteins known as short-chain dehydrogenases. When the x-ray structure of dihydropteridine reductase is correlated with conserved amino acid sequences characteristic of this enzyme class, two important common structural regions can be identified. One is close to the protein N terminus and serves as the cofactor binding site, while a second conserved feature makes up the inner surface of an alpha-helix in which a tyrosine side chain is positioned in close proximity to a lysine residue four residues downstream in the sequence. The main function of this Tyr-Lys couple may be to facilitate tyrosine hydroxyl group participation in proton transfer. Thus, it appears that there is a distinctive common mechanism for this group of short-chain or pyridine dinucleotide-dependent oxidoreductases that is different from their higher molecular weight counterparts.
authors.affiliation: University of California at San Diego, La Jolla 92093-0317.
authors.forename: K I
authors.initials: KI
authors.lastname: Varughese
authors.forename: N H
authors.initials: NH
authors.lastname: Xuong
authors.forename: P M
authors.initials: PM
authors.lastname: Kiefer
authors.forename: D A
authors.initials: DA
authors.lastname: Matthews
authors.forename: J M
authors.initials: JM
authors.lastname: Whiteley
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002384:Catalysis; D004093:Dihydropteridine Reductase / Q000737:chemistry*; D008958:Models, Molecular; D008969:Molecular Sequence Data; D017434:Protein Structure, Tertiary; D051381:Rats; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid
chemical_list: D004093:Dihydropteridine Reductase