1xtu | pdb_00001xtu

Sulfolobus solfataricus uracil phosphoribosyltransferase in complex with uridine 5'-monophosphate (UMP) and cytidine 5'-triphosphate (CTP)

spinqualitylabelsall models 1xtu, resolution 2.80Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 1xtu is a 8 chain structure with sequence from Sulfolobus solfataricus. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: CTP, U5P Related: 1xtt, 1xtv Gene: upp (Sulfolobus solfataricus) Activity: Uracil phosphoribosyltransferase, with EC number 2.4.2.9 Resources: FirstGlance, OCA, RCSB, PDBsum 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 Uracil phosphoribosyltransferase (UPRTase) catalyzes the conversion of 5-phosphate-alpha-1-diphosphate (PRPP) and uracil to uridine 5'-monophosphate (UMP) and diphosphate. The UPRTase from Sulfolobus solfataricus has a unique regulation by nucleoside triphosphates compared to UPRTases from other organisms. To understand the allosteric regulation, crystal structures were determined for S. solfataricus UPRTase in complex with UMP and with UMP and the allosteric inhibitor CTP. Also, a structure with UMP bound in half of the active sites was determined. All three complexes form tetramers but reveal differences in the subunits and their relative arrangement. In the UPRTase-UMP complex, the peptide bond between a conserved arginine residue (Arg80) and the preceding residue (Leu79) adopts a cis conformation in half of the subunits and a trans conformation in the other half and the tetramer comprises two cis-trans dimers. In contrast, four identical subunits compose the UPRTase-UMP-CTP tetramer. CTP binding affects the conformation of Arg80, and the Arg80 conformation in the UPRTase-UMP-CTP complex leaves no room for binding of the substrate PRPP. The different conformations of Arg80 coupled to rearrangements in the quaternary structure imply that this residue plays a major role in regulation of the enzyme and in communication between subunits. The ribose ring of UMP adopts alternative conformations in the cis and trans subunits of the UPRTase-UMP tetramer with associated differences in the interactions of the catalytically important Asp209. The active-site differences have been related to proposed kinetic models and provide an explanation for the regulatory significance of the C-terminal Gly216. Allosteric regulation and communication between subunits in uracil phosphoribosyltransferase from Sulfolobus solfataricus.,Arent S, Harris P, Jensen KF, Larsen S Biochemistry. 2005 Jan 25;44(3):883-92. PMID:15654744 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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