4f0k

UNACTIVATED RUBISCO with MAGNESIUM AND CARBON DIOXIDE BOUND

spinqualitylabelsall models 4f0k, resolution 2.05Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 4f0k is a 2 chain structure with sequence from Galdieria sulphuraria. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 2.05Å Ligands: CL, CO2, GOL, MG, SNC Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function RBL_GALSU RuBisCO catalyzes two reactions: the carboxylation of D-ribulose 1,5-bisphosphate, the primary event in carbon dioxide fixation, as well as the oxidative fragmentation of the pentose substrate in the photorespiration process. Both reactions occur simultaneously and in competition at the same active site.[HAMAP-Rule:MF_01338] Publication Abstract from PubMed Ribulose 1,5-bisphosphate carboxylase/oxygenase (RuBisCO) is a crucial enzyme in carbon fixation and the most abundant protein on earth. It has been studied extensively by biochemical and structural methods; however, the most essential activation step has not yet been described. Here, we describe the mechanistic details of Lys carbamylation that leads to RuBisCO activation by atmospheric CO(2). We report two crystal structures of nitrosylated RuBisCO from the red algae Galdieria sulphuraria with O(2) and CO(2) bound at the active site. G. sulphuraria RuBisCO is inhibited by cysteine nitrosylation that results in trapping of these gaseous ligands. The structure with CO(2) defines an elusive, preactivation complex that contains a metal cation Mg(2+) surrounded by three H(2)O/OH molecules. Both structures suggest the mechanism for discriminating gaseous ligands by their quadrupole electric moments. We describe conformational changes that allow for intermittent binding of the metal ion required for activation. On the basis of these structures we propose the individual steps of the activation mechanism. Knowledge of all these elements is indispensable for engineering RuBisCO into a more efficient enzyme for crop enhancement or as a remedy to global warming. Structural mechanism of RuBisCO activation by carbamylation of the active site lysine.,Stec B Proc Natl Acad Sci U S A. 2012 Oct 29. PMID:23112176 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also RuBisCO 3D structures

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