3ph3

Clostridium thermocellum Ribose-5-Phosphate Isomerase B with d-ribose

spinqualitylabelsall models 3ph3, resolution 2.07Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 3ph3 is a 2 chain structure with sequence from Acetivibrio thermocellus ATCC 27405. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 2.07Å Ligands: RB5 Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function A3DIL8_ACET2 Publication Abstract from PubMed Ribose-5-phosphate isomerase (Rpi) catalyzes the conversion of D: -ribose 5-phosphate (R5P) to D: -ribulose 5-phosphate, which is an important step in the non-oxidative pathway of the pentose phosphate pathway and the Calvin cycle of photosynthesis. Recently, Rpis have been used to produce valuable rare sugars for industrial purposes. Of the Rpis, D: -ribose-5-phosphate isomerase B from Clostridium thermocellum (CtRpi) has the fastest reactions kinetics. While Thermotoga maritime Rpi (TmRpi) has the same substrate specificity as CtRpi, the overall activity of CtRpi is approximately 200-fold higher than that of TmRpi. To understand the structural basis of these kinetic differences, we determined the crystal structures, at 2.1-A resolution or higher, of CtRpi alone and bound to its substrates, R5P, D: -ribose, and D: -allose. Structural comparisons of CtRpi and TmRpi showed overall conservation of their structures with two notable differences. First, the volume of the CtRpi substrate binding pocket (SBP) was 20% less than that of the TmRpi SBP. Second, the residues next to the sugar-ring opening catalytic residue (His98) were different. We switched the key residues, involved in SBP shaping or catalysis, between CtRpi and TmRpi by site-directed mutagenesis, and studied the enzyme kinetics of the mutants. We found that tight interactions between the two monomers, narrow SBP width, and the residues near the catalytic residue are all critical for the fast enzyme kinetics of CtRpi. Crystal structure of Clostridium thermocellum ribose-5-phosphate isomerase B reveals properties critical for fast enzyme kinetics.,Jung J, Kim JK, Yeom SJ, Ahn YJ, Oh DK, Kang LW Appl Microbiol Biotechnol. 2011 Apr;90(2):517-27. Epub 2011 Jan 21. PMID:21253719 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Ribose-5-phosphate isomerase 3D structures

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