1a7j
From Proteopedia
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PHOSPHORIBULOKINASE FROM RHODOBACTER SPHEROIDES
Overview
The essential photosynthetic enzyme phosphoribulokinase (PRK) is, responsible for the conversion of ribulose 5-phosphate (Ru5P) to ribulose, 1,5-bisphosphate, the substrate for the CO2 fixing enzyme ribulose, 1,5-bisphosphate carboxylase/oxygenase (Rubisco). We have determined the, structure of the octameric bacterial form of PRK to a resolution of 2.5 A., The protein is folded into a seven-member mixed beta-sheet surrounded by, alpha-helices, giving the overall appearance of the nucleotide, monophosphate family of kinases. Homology with the nucleotide, monophosphate kinases suggests a number of amino acid residues that are, likely to be important in catalysis and suggests the roles of some amino, acid residues that have been mutated prior to the determination of the, structure. Further, sequence identity across eukaryotic and prokaryotic, species and a calculation of the buried surface area suggests the identity, within the octamer of a dimer conserved throughout evolution. The width of, the groove leading to the active site is consistent with an oriented, molecule of thioredoxin controlling the oxidation state of two cysteines, that regulate activity in the eukaryotic enzymes. Although neither Asp 42, nor Asp 169 can be definitively assigned as the catalytic base, the, crystal structure suggests the location of a ribulose 5-phosphate binding, site and suggests a role for several of the conserved basic residues.
About this Structure
1A7J is a Single protein structure of sequence from Rhodobacter sphaeroides with as ligand. Active as Phosphoribulokinase, with EC number 2.7.1.19 Known structural/functional Site: . Full crystallographic information is available from OCA.
Reference
The crystal structure of phosphoribulokinase from Rhodobacter sphaeroides reveals a fold similar to that of adenylate kinase., Harrison DH, Runquist JA, Holub A, Miziorko HM, Biochemistry. 1998 Apr 14;37(15):5074-85. PMID:9548738
Page seeded by OCA on Sun Feb 3 09:29:28 2008
