title: Crystal structure of NAD-dependent malate dehydrogenase complexed with NADP(H).
abstract: For better understanding of the coenzyme specificity in NAD-dependent MDH (tMDH) from Thermus flavus AT-62, we determined the crystal structures of tMDH-NADP(H) complex at maximally 1.65 A resolution. The overall structure is almost the same as that of the tMDH-NADH complex. However, NADP(H) binds to tMDH in the reverse orientation, where adenine occupies the position near the catalytic center and nicotinamide is positioned at the adenine binding site of the tMDH-NADH complex. Consistent with this, kinetic analysis of the malate-oxidizing reaction revealed that NADP(+) inhibited tMDH at high concentrations. This has provided the first evidence for the alternative binding mode of the nicotinamide coenzyme, that has pseudo-symmetry in its structure, in a single enzyme.
authors: Biotechnology Research Center, The University of Tokyo, Bunkyo-ku, Tokyo 113-8657, Japan.
authors: Takeo
authors: T
authors: Tomita
authors: Shinya
authors: S
authors: Fushinobu
authors: Tomohisa
authors: T
authors: Kuzuyama
authors: Makoto
authors: M
authors: Nishiyama
mesh_terms: D001665:Binding Sites; D003198:Computer Simulation; D003461:Crystallography; D008291:Malate Dehydrogenase / Q000032:analysis / Q000737:chemistry* / Q000648:ultrastructure*; D050538:Malate Dehydrogenase (NADP+); D008956:Models, Chemical; D008958:Models, Molecular; D046912:Multiprotein Complexes / Q000032:analysis / Q000737:chemistry / Q000648:ultrastructure; D009249:NADP / Q000032:analysis / Q000737:chemistry* / Q000648:ultrastructure*; D011485:Protein Binding; D011487:Protein Conformation
chemical_list: D046912:Multiprotein Complexes; D009249:NADP; D008291:Malate Dehydrogenase; D050538:Malate Dehydrogenase (NADP+)