2xdq

Dark Operative Protochlorophyllide Oxidoreductase (ChlN-ChlB)2 Complex

spinqualitylabelsall models 2xdq, resolution 2.40Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 2xdq is a 2 chain structure with sequence from Thermosynechococcus vestitus. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 2.4Å Ligands: MGX, SO4 Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function CHLN_THEVB Component of the dark-operative protochlorophyllide reductase (DPOR) that uses Mg-ATP and reduced ferredoxin to reduce ring D of protochlorophyllide (Pchlide) to form chlorophyllide a (Chlide). This reaction is light-independent. The NB-protein (ChlN-ChlB) is the catalytic component of the complex.[HAMAP-Rule:MF_00352] Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMed During (bacterio)chlorophyll biosynthesis of many photosynthetically active organisms, dark operative protochlorophyllide oxidoreductase (DPOR) catalyzes the two-electron reduction of ring D of protochlorophyllide to form chlorophyllide. DPOR is composed of the subunits ChlL, ChlN, and ChlB. Homodimeric ChlL(2) bearing an intersubunit [4Fe-4S] cluster is an ATP-dependent reductase transferring single electrons to the heterotetrameric (ChlN/ChlB)(2) complex. The latter contains two intersubunit [4Fe-4S] clusters and two protochlorophyllide binding sites, respectively. Here we present the crystal structure of the catalytic (ChlN/ChlB)(2) complex of DPOR from the cyanobacterium Thermosynechococcus elongatus at a resolution of 2.4 A. Subunits ChlN and ChlB exhibit a related architecture of three subdomains each built around a central, parallel beta-sheet surrounded by alpha-helices. The (ChlN/ChlB)(2) crystal structure reveals a [4Fe-4S] cluster coordinated by an aspartate oxygen alongside three cysteine ligands. Two equivalent substrate binding sites enriched in aromatic residues for protochlorophyllide substrate binding are located at the interface of each ChlN/ChlB half-tetramer. The complete octameric (ChlN/ChlB)(2)(ChlL(2))(2) complex of DPOR was modeled based on the crystal structure and earlier functional studies. The electron transfer pathway via the various redox centers of DPOR to the substrate is proposed. Crystal structure of the nitrogenase-like dark operative protochlorophyllide oxidoreductase catalytic complex (ChlN/ChlB)2.,Brocker MJ, Schomburg S, Heinz DW, Jahn D, Schubert WD, Moser J J Biol Chem. 2010 Aug 27;285(35):27336-45. Epub 2010 Jun 17. PMID:20558746 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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