title: Nicotinamide is a specific inhibitor of dark-operative protochlorophyllide oxidoreductase, a nitrogenase-like enzyme, from Rhodobacter capsulatus.
abstract: Dark-operative protochlorophyllide oxidoreductase (DPOR) is a nitrogenase-like enzyme consisting of two components, L-protein as a reductase component and NB-protein as a catalytic component. Elucidation of the crystal structures of NB-protein (Muraki et al., Nature 2010, 465: 110-114) has enabled us to study its reaction mechanism in combination with biochemical analysis. Here we demonstrate that nicotinamide (NA) inhibits DPOR activity by blocking the electron transfer from L-protein to NB-protein. A reaction scheme of DPOR, in which the binding of protochlorophyllide (Pchlide) to the NB-protein precedes the electron transfer from the L-protein, is proposed based on the NA effects.
authors: Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya 464-8601, Japan.
authors: Jiro
authors: J
authors: Nomata
authors: Toru
authors: T
authors: Kondo
authors: Shigeru
authors: S
authors: Itoh
authors: Yuichi
authors: Y
authors: Fujita
mesh_terms: D001426:Bacterial Proteins / Q000037:antagonists & inhibitors / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D055162:Biocatalysis; D004579:Electron Transport; D057075:Enzyme Assays; D004926:Escherichia coli / Q000235:genetics; D007700:Kinetics; D062105:Molecular Docking Simulation; D009536:Niacinamide / Q000737:chemistry*; D044925:Oxidoreductases Acting on CH-CH Group Donors / Q000037:antagonists & inhibitors / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D011521:Protochlorophyllide / Q000737:chemistry; D011994:Recombinant Proteins / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D016354:Rhodobacter capsulatus / Q000737:chemistry* / Q000201:enzymology / Q000235:genetics
chemical_list: D001426:Bacterial Proteins; D011994:Recombinant Proteins; D011521:Protochlorophyllide; D009536:Niacinamide; D044925:Oxidoreductases Acting on CH-CH Group Donors; C023886:protochlorophyllide reductase
keywords: Bacteriochlorophyll; Bchl; Chl; Chlide; Chlorophyll; DPOR; FeS cluster; LPOR; NA; Nitrogenase; Pchlide; Protochlorophyllide; bacteriochlorophyll; chlorophyll; chlorophyllide a; dark-operative protochlorophyllide oxidoreductase; light-dependent protochlorophyllide oxidoreductase; nicotinamide; protochlorophyllide