4yub | pdb_00004yub

Crystal structure of human Nicotinic Acid Phosphoribosyltransferase

spinqualitylabelsall models 4yub, resolution 2.90Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 4yub is a 2 chain structure with sequence from Human. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Gene: NAPRT, FHIP, NAPRT1 (HUMAN) Activity: Nicotinate phosphoribosyltransferase, with EC number 6.3.4.21 Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function [PNCB_HUMAN] Catalyzes the conversion of nicotinic acid (NA) to NA mononucleotide (NaMN). Essential for NA to increase cellular NAD levels and prevent oxidative stress of the cells. Catalyzes the synthesis of beta-nicotinate D-ribonucleotide from nicotinate and 5-phospho-D-ribose 1-phosphate at the expense of ATP. Publication Abstract from PubMed Nicotinic acid phosphoribosyltransferase (EC 2.4.2.11) (NaPRTase) is the rate-limiting enzyme in the three-step Preiss-Handler pathway for the biosynthesis of NAD. The enzyme catalyzes the conversion of nicotinic acid (Na) and 5-phosphoribosyl-1-pyrophosphate (PRPP) to nicotinic acid mononucleotide (NaMN) and pyrophosphate (PPi). Several studies have underlined the importance of NaPRTase for NAD homeostasis in mammals, but no crystallographic data are available for this enzyme from higher eukaryotes. Here, we report the crystal structure of human NaPRTase that was solved by molecular replacement at a resolution of 2.9 A in its ligand-free form. Our structural data allow the assignment of human NaPRTase to the type II phosphoribosyltransferase subfamily and reveal that the enzyme consists of two domains and functions as a dimer with the active site located at the interface of the monomers. The substrate-binding mode was analyzed by molecular docking simulation and provides hints into the catalytic mechanism. Moreover, structural comparison of human NaPRTase with the other two human type II phosphoribosyltransferases involved in NAD biosynthesis, quinolinate phosphoribosyltransferase and nicotinamide phosphoribosyltransferase, reveals that while the three enzymes share a conserved overall structure, a few distinctive structural traits can be identified. In particular, we show that NaPRTase lacks a tunnel that, in nicotinamide phosphoribosiltransferase, represents the binding site of its potent and selective inhibitor FK866, currently used in clinical trials as an antitumoral agent. Crystal structure of human nicotinic acid phosphoribosyltransferase.,Marletta AS, Massarotti A, Orsomando G, Magni G, Rizzi M, Garavaglia S FEBS Open Bio. 2015 May 7;5:419-28. doi: 10.1016/j.fob.2015.05.002. eCollection, 2015. PMID:26042198 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Phosphoribosyltransferase

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