Publications

• Structural insights into Xanthomonas campestris pv. campestris NAD+ biosynthesis via the NAM salvage pathway.

  Xu G., Ma J., Fang Q., Peng Q., Jiao X., Hu W., Zhao Q., Kong Y., Liu F., Shi X., Tang D.J., Tang J.L., Ming Z.

  Nicotinamide phosphoribosyltransferase (NAMPT) plays an important role in the biosynthesis of nicotinamide adenine dinucleotide (NAD⁺) via the nicotinamide (NAM) salvage pathway. While the structural biochemistry of eukaryote NAMPT has been well studied, the catalysis mechanism of proka ... >> More

  Nicotinamide phosphoribosyltransferase (NAMPT) plays an important role in the biosynthesis of nicotinamide adenine dinucleotide (NAD⁺) via the nicotinamide (NAM) salvage pathway. While the structural biochemistry of eukaryote NAMPT has been well studied, the catalysis mechanism of prokaryote NAMPT at the molecular level remains largely unclear. Here, we demonstrated the NAMPT-mediated salvage pathway is functional in the Gram-negative phytopathogenic bacterium Xanthomonas campestris pv. campestris (Xcc) for the synthesis of NAD⁺, and the enzyme activity of NAMPT in this bacterium is significantly higher than that of human NAMPT in vitro. Our structural analyses of Xcc NAMPT, both in isolation and in complex with either the substrate NAM or the product nicotinamide mononucleotide (NMN), uncovered significant details of substrate recognition. Specifically, we revealed the presence of a NAM binding tunnel that connects the active site, and this tunnel is essential for both catalysis and inhibitor binding. We further demonstrated that NAM binding in the tunnel has a positive cooperative effect with NAM binding in the catalytic site. Additionally, we discovered that phosphorylation of the His residue at position 229 enhances the substrate binding affinity of Xcc NAMPT and is important for its catalytic activity. This work reveals the importance of NAMPT in bacterial NAD⁺ synthesis and provides insights into the substrate recognition and the catalytic mechanism of bacterial type II phosphoribosyltransferases. << Less

  Commun. Biol. 7:255-255(2024) [PubMed] [EuropePMC]

• Pre-B-cell colony-enhancing factor, whose expression is up-regulated in activated lymphocytes, is a nicotinamide phosphoribosyltransferase, a cytosolic enzyme involved in NAD biosynthesis.

  Rongvaux A., Shea R.J., Mulks M.H., Gigot D., Urbain J., Leo O., Andris F.

  The murine homologue of the previously identified human "pre-B-cell colony-enhancing factor" (PBEF) gene coding for a putative cytokine has been identified by screening a subtractive library enriched in genes expressed in activated T lymphocytes. Unlike most cytokine genes known to date, the PBEF ... >> More

  The murine homologue of the previously identified human "pre-B-cell colony-enhancing factor" (PBEF) gene coding for a putative cytokine has been identified by screening a subtractive library enriched in genes expressed in activated T lymphocytes. Unlike most cytokine genes known to date, the PBEF gene is ubiquitously expressed in lymphoid and non-lymphoid tissues and displays significant homology with genes from primitive metazoans (marine sponges) and prokaryotic organisms. Recently, a bacterial protein encoded by nadV, a gene from the prokaryote Haemophilus ducreyi displaying significant homology with PBEF, has been identified as a nicotinamide phosphoribosyltranferase (NAmPRTase), an enzyme involved in nicotinamide adenine dinucleotide (NAD) biosynthesis. Using a panel of antibodies to murine PBEF, we demonstrate in this work that, similarly to its microbial counterpart, the murine protein is a NAmPRTase, catalyzing the condensation of nicotinamide with 5-phosphoribosyl-1-pyrophosphate to yield nicotinamide mononucleotide, an intermediate in the biosynthesis of NAD. The role of PBEF as a NAmPRTase was further confirmed by showing that the mouse gene was able to confer the ability to grow in the absence of NAD to a NAmPRTase-defective bacterial strain. The present findings are in keeping with the ubiquitous nature of this protein, and indicate that NAD biosynthesis may play an important role in lymphocyte activation. << Less

  Eur. J. Immunol. 32:3225-3234(2002) [PubMed] [EuropePMC]

• Molecular basis for the inhibition of human NMPRTase, a novel target for anticancer agents.

  Khan J.A., Tao X., Tong L.

  Nicotinamide phosphoribosyltransferase (NMPRTase) has a crucial role in the salvage pathway of NAD+ biosynthesis, and a potent inhibitor of NMPRTase, FK866, can reduce cellular NAD+ levels and induce apoptosis in tumors. We have determined the crystal structures at up to 2.1-A resolution of human ... >> More

  Nicotinamide phosphoribosyltransferase (NMPRTase) has a crucial role in the salvage pathway of NAD+ biosynthesis, and a potent inhibitor of NMPRTase, FK866, can reduce cellular NAD+ levels and induce apoptosis in tumors. We have determined the crystal structures at up to 2.1-A resolution of human and murine NMPRTase, alone and in complex with the reaction product nicotinamide mononucleotide or the inhibitor FK866. The structures suggest that Asp219 is a determinant of substrate specificity of NMPRTase, which is confirmed by our mutagenesis studies. FK866 is bound in a tunnel at the interface of the NMPRTase dimer, and mutations in this binding site can abolish the inhibition by FK866. Contrary to current knowledge, the structures show that FK866 should compete directly with the nicotinamide substrate. Our structural and biochemical studies provide a starting point for the development of new anticancer agents. << Less

  Nat. Struct. Mol. Biol. 13:582-588(2006) [PubMed] [EuropePMC]

• Identification of structural determinants of nicotinamide phosphoribosyl transferase (NAMPT) activity and substrate selectivity.

  Houry D., Raasakka A., Ferrario E., Niere M., Bifulco E., Kursula P., Ziegler M.

  NAD homeostasis in mammals requires the salvage of nicotinamide (Nam), which is cleaved from NAD⁺ by sirtuins, PARPs, and other NAD⁺-dependent signaling enzymes. Nam phosphoribosyltransferase (NAMPT) catalyzes the rate-limiting step in vitamin B3 salvage, whereby Nam reacts w ... >> More

  NAD homeostasis in mammals requires the salvage of nicotinamide (Nam), which is cleaved from NAD⁺ by sirtuins, PARPs, and other NAD⁺-dependent signaling enzymes. Nam phosphoribosyltransferase (NAMPT) catalyzes the rate-limiting step in vitamin B3 salvage, whereby Nam reacts with phosphoribosyl pyrophosphate (PRPP) to form nicotinamide mononucleotide. NAMPT has a high affinity towards Nam, which is further enhanced by autophosphorylation of His247. The mechanism of this enhancement has remained unknown. Here, we present high-resolution crystal structures and biochemical data that provide reasoning for the increased affinity of the phosphorylated NAMPT for its substrate. Structural and kinetic analyses suggest a mechanism that includes Mg²⁺ coordination by phospho-His247, such that PRPP is stabilized in a position highly favorable for catalysis. Under these conditions, nicotinic acid (NA) can serve as a substrate. Moreover, we demonstrate that a stretch of 10 amino acids, present only in NAMPTs from deuterostomes, facilitates conformational plasticity and stabilizes the chemically unstable phosphorylation of His247. Thereby the apparent substrate affinity is considerably enhanced compared to prokaryotic NAMPTs. Collectively, our study provides a structural basis for the important function of NAMPT to recycle Nam into NAD biosynthesis with high affinity. << Less

  J Struct Biol 215:108004-108004(2023) [PubMed] [EuropePMC]

• Crystal structure of visfatin/pre-B cell colony-enhancing factor 1/nicotinamide phosphoribosyltransferase, free and in complex with the anti-cancer agent FK-866.

  Kim M.-K., Lee J.H., Kim H., Park S.J., Kim S.H., Kang G.B., Lee Y.S., Kim J.B., Kim K.K., Suh S.W., Eom S.H.

  Visfatin/pre-B cell colony-enhancing factor 1 (PBEF)/nicotinamide phosphoribosyltransferase (NAmPRTase) is a multifunctional protein having phosphoribosyltransferase, cytokine and adipokine activities. Originally isolated as a cytokine promoting the differentiation of B cell precursors, it was rec ... >> More

  Visfatin/pre-B cell colony-enhancing factor 1 (PBEF)/nicotinamide phosphoribosyltransferase (NAmPRTase) is a multifunctional protein having phosphoribosyltransferase, cytokine and adipokine activities. Originally isolated as a cytokine promoting the differentiation of B cell precursors, it was recently suggested to act as an insulin analog via the insulin receptor. Here, we describe the first crystal structure of visfatin in three different forms: apo and in complex with either nicotinamide mononucleotide (NMN) or the NAmPRTase inhibitor FK-866 which was developed as an anti-cancer agent, interferes with NAD biosynthesis, showing a particularly high specificity for NAmPRTase. The crystal structures of the complexes with either NMN or FK-866 show that the enzymatic active site of visfatin is optimized for nicotinamide binding and that the nicotinamide-binding site is important for inhibition by FK-866. Interestingly, visfatin mimics insulin signaling by binding to the insulin receptor with an affinity similar to that of insulin and does not share the binding site with insulin on the insulin receptor. To predict binding sites, the potential interaction patches of visfatin and the L1-CR-L2 domain of insulin receptor were generated and analyzed. Although the relationship between the insulin-mimetic property and the enzymatic function of visfatin has not been clearly established, our structures raise the intriguing possibility that the glucose metabolism and the NAD biosynthesis are linked by visfatin. << Less

  J. Mol. Biol. 362:66-77(2006) [PubMed] [EuropePMC]