title: Crystal structure of human pyrroline-5-carboxylate reductase.
abstract: Pyrroline-5-carboxylate reductase (P5CR) is a universal housekeeping enzyme that catalyzes the reduction of Delta(1)-pyrroline-5-carboxylate (P5C) to proline using NAD(P)H as the cofactor. The enzymatic cycle between P5C and proline is very important for the regulation of amino acid metabolism, intracellular redox potential, and apoptosis. Here, we present the 2.8 Angstroms resolution structure of the P5CR apo enzyme, its 3.1 Angstroms resolution ternary complex with NAD(P)H and substrate-analog. The refined structures demonstrate a decameric architecture with five homodimer subunits and ten catalytic sites arranged around a peripheral circular groove. Mutagenesis and kinetic studies reveal the pivotal roles of the dinucleotide-binding Rossmann motif and residue Glu221 in the human enzyme. Human P5CR is thermostable and the crystals were grown at 37 degrees C. The enzyme is implicated in oxidation of the anti-tumor drug thioproline.
authors.affiliation: Tsinghua-IBP Joint Research Group for Structural Biology, Tsinghua University, Beijing, China.
authors.forename: Zhaohui
authors.initials: Z
authors.lastname: Meng
authors.forename: Zhiyong
authors.initials: Z
authors.lastname: Lou
authors.forename: Zhe
authors.initials: Z
authors.lastname: Liu
authors.forename: Ming
authors.initials: M
authors.lastname: Li
authors.forename: Xiaodong
authors.initials: X
authors.lastname: Zhao
authors.forename: Mark
authors.initials: M
authors.lastname: Bartlam
authors.forename: Zihe
authors.initials: Z
authors.lastname: Rao
mesh_terms: D000595:Amino Acid Sequence; D001665:Binding Sites / Q000235:genetics; D019281:Dimerization; D006801:Humans; D008958:Models, Molecular; D008969:Molecular Sequence Data; D016296:Mutagenesis / Q000235:genetics; D017433:Protein Structure, Secondary; D011762:Pyrroline Carboxylate Reductases / Q000037:antagonists & inhibitors / Q000737:chemistry*; D016415:Sequence Alignment; D013297:Streptococcus pyogenes / Q000201:enzymology; D000097502:delta-1-Pyrroline-5-Carboxylate Reductase
chemical_list: D011762:Pyrroline Carboxylate Reductases; D000097502:delta-1-Pyrroline-5-Carboxylate Reductase