2JBM
QPRTASE STRUCTURE FROM HUMAN
Summary for 2JBM
| Entry DOI | 10.2210/pdb2jbm/pdb |
| Descriptor | NICOTINATE-NUCLEOTIDE PYROPHOSPHORYLASE, S,R MESO-TARTARIC ACID (3 entities in total) |
| Functional Keywords | nad, enzyme, metabolism, transferase, polymorphism, glycosyltransferase, pyridine nucleotide biosynthesis |
| Biological source | HOMO SAPIENS (HUMAN) |
| Total number of polymer chains | 12 |
| Total formula weight | 373484.71 |
| Authors | Liu, H.,Naismith, J.H. (deposition date: 2006-12-08, release date: 2007-11-13, Last modification date: 2024-05-08) |
| Primary citation | Liu, H.,Woznica, K.,Catton, G.,Crawford, A.,Bottinf, N.,Naismith, J.H. Structural and Kinetic Characterization of Quinolinate Phosphoribosyltransferase (Hqprtase) from Homo Sapiens. J.Mol.Biol., 373:755-, 2007 Cited by PubMed Abstract: Human quinolinate phosphoribosyltransferase (EC 2.4.2.19) (hQPRTase) is a member of the type II phosphoribosyltransferase family involved in the catabolism of quinolinic acid (QA). It catalyses the formation of nicotinic acid mononucleotide from quinolinic acid, which involves a phosphoribosyl transfer reaction followed by decarboxylation. hQPRTase has been implicated in a number of neurological conditions and in order to study it further, we have carried out structural and kinetic studies on recombinant hQPRTase. The structure of the fully active enzyme overexpressed in Escherichia coli was solved using multiwavelength methods to a resolution of 2.0 A. hQPRTase has a alpha/beta barrel fold sharing a similar overall structure with the bacterial QPRTases. The active site of hQPRTase is located at an alpha/beta open sandwich structure that serves as a cup for the alpha/beta barrel of the adjacent subunit with a QA binding site consisting of three arginine residues (R102, R138 and R161) and two lysine residues (K139 and K171). Mutation of these residues affected substrate binding or abolished the enzymatic activity. The kinetics of the human enzyme are different to the bacterial enzymes studied, hQPRTase is inhibited competitively and non-competitively by one of its substrates, 5-phosphoribosylpyrophosphate (PRPP). The human enzyme adopts a hexameric arrangement, which places the active sites in close proximity to each other. PubMed: 17868694DOI: 10.1016/J.JMB.2007.08.043 PDB entries with the same primary citation |
| Experimental method | X-RAY DIFFRACTION (2 Å) |
Structure validation
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