4KWV
Crystal Structure of human apo-QPRT
Summary for 4KWV
| Entry DOI | 10.2210/pdb4kwv/pdb |
| Related | 4KWW |
| Descriptor | Nicotinate-nucleotide pyrophosphorylase [carboxylating] (2 entities in total) |
| Functional Keywords | nad, metabolism, type ii phosphoribosyltransferase, quinolinic acid, prpp, brain, transferase |
| Biological source | Homo sapiens (human) |
| Total number of polymer chains | 6 |
| Total formula weight | 187042.96 |
| Authors | Malik, S.S.,Patterson, D.N.,Ncube, Z.,Toth, E.A. (deposition date: 2013-05-24, release date: 2013-10-02, Last modification date: 2023-09-20) |
| Primary citation | Malik, S.S.,Patterson, D.N.,Ncube, Z.,Toth, E.A. The crystal structure of human quinolinic acid phosphoribosyltransferase in complex with its inhibitor phthalic acid. Proteins, 82:405-414, 2014 Cited by PubMed Abstract: Quinolinic acid (QA), a biologically potent but neurodestructive metabolite is catabolized by quinolinic acid phosphoribosyltransferase (QPRT) in the first step of the de novo NAD(+) biosynthesis pathway. This puts QPRT at the junction of two different pathways, that is, de novo NAD(+) biosynthesis and the kynurenine pathway of tryptophan degradation. Thus, QPRT is an important enzyme in terms of its biological impact and its potential as a therapeutic target. Here, we report the crystal structure of human QPRT bound to its inhibitor phthalic acid (PHT) and kinetic analysis of PHT inhibition of human QPRT. This structure, determined at 2.55 Å resolution, shows an elaborate hydrogen bonding network that helps in recognition of PHT and consequently its substrate QA. In addition to this hydrogen bonding network, we observe extensive van der Waals contacts with the PHT ring that might be important for correctly orientating the substrate QA during catalysis. Moreover, our crystal form allows us to observe an intact hexamer in both the apo- and PHT-bound forms in the same crystal system, which provides a direct comparison of unique subunit interfaces formed in hexameric human QPRT. We call these interfaces "nondimeric interfaces" to distinguish them from the typical dimeric interfaces observed in all QPRTs. We observe significant changes in the nondimeric interfaces in the QPRT hexamer upon binding PHT. Thus, the new structural and functional features of this enzyme we describe here will aid in understanding the function of hexameric QPRTs, which includes all eukaryotic and select prokaryotic QPRTs. PubMed: 24038671DOI: 10.1002/prot.24406 PDB entries with the same primary citation |
| Experimental method | X-RAY DIFFRACTION (2.797 Å) |
Structure validation
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