5yg6

Crystal structure of ribose-1,5-bisphosphate isomerase mutant C135S from Pyrococcus horikoshii OT3 in complex with ribose-1,5-bisphosphate and GMP

spinqualitylabelsall models 5yg6, resolution 2.35Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 5yg6 is a 3 chain structure with sequence from Pyrococcus horikoshii OT3. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 2.35Å Ligands: 5GP, K, MPD, RI2 Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function R15PI_PYRHO Catalyzes the isomerization of ribose 1,5-bisphosphate (R15P) to ribulose 1,5-bisphosphate (RuBP), the CO(2) acceptor and substrate for RubisCO. Functions in an archaeal AMP degradation pathway, together with AMP phosphorylase and RubisCO (By similarity). Publication Abstract from PubMed The homologues of the regulatory subunits of eukaryotic translation initiation factor 2B (eIF2B) are assumed to be present in archaea. Likewise, an ORF, PH0208 in Pyrococcus horikoshii OT3 have been proposed to encode one of the homologues of regulatory subunits of eIF2B. However, PH0208 protein also shares sequence similarity with a functionally non-related enzyme, ribose-1,5-bisphosphate isomerase (R15Pi), involved in conversion of ribose-1,5-bisphosphate (R15P) to ribulose-1,5-bisphosphate (RuBP) in an AMP-dependent manner. Herein, we have determined the crystal structure of PH0208 protein in order to decipher its true function. Although structurally similar to the regulatory subunits of eIF2B, the ability to bind R15P and RuBP suggests that PH0208 would function as R15Pi. Additionally, this study for the first time reports the binding sites of AMP and GMP in R15Pi. The AMP binding site in PH0208 protein clarified the role of AMP in providing structural stability to R15Pi. The binding of GMP to the 'AMP binding site' in addition to its own binding site indicates that GMP might also execute a similar function, though with less specificity. Furthermore, we have utilized the resemblance between PH0208 and the regulatory subunits of eIF2B to propose a model for the regulatory mechanism of eIF2B in eukaryotes. A presumed homologue of the regulatory subunits of eIF2B functions as ribose-1,5-bisphosphate isomerase in Pyrococcus horikoshii OT3.,Gogoi P, Kanaujia SP Sci Rep. 2018 Jan 30;8(1):1891. doi: 10.1038/s41598-018-20418-w. PMID:29382938 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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