Binding status of NCA. The three hydrogen bonding interactions (His-113 to NCA oxygen atom, Asp-62 to NCA nitrogen atom and His-113 to Asp-62) sustain the conformational position of the ligand. The Zn2+ keeps the strong binding to the Title Loaded From File ligand that was also present in L. infantum PNC (PDB 3R2J). In C. teleta the Trp-110 (hydrophobic interaction) and Tyr-147 (H-bond interaction) are the residues from the active site that play an important role in the ligandEvolution of NAMPT and NicotinamidaseFigure 4. Syntenic organization of NAMPT homologues. Gene order and organization are represented for several lineages, and show conservation of microsynteny in chordates. H. sapiens chromosome 7, M. musculus chromosome 12, D. rerio chromosome 4, B. floridae scaffold 633, N. vectensis scaffold 360, T. adhaerens scaffold 2 and M. brevicollis scaffold 7 are displayed and dots indicate intervals containing multiple genes (.4). doi:10.1371/journal.pone.0064674.greceptor interaction. As in B. floridae, the His-113 has a hydrogen bond connection with NCA. Two other H-bond interactions not present in L. infantum PNC (Ser-70 and Lys-108) appear to be important to ligand binding. The interaction between Zn2+ and ligand is maintained. Although no significant changes in ligand conformation were observed, hydrogen bonds in N. vectensis were not predicted. When compared to 3R2J, hydrophobic interactions Cys-21, Trp-99, Ala-169 and Cys-173 are kept for the active site residues. Hydrophobic interactions for the catalytic residue Cys173 are present, as well as a newly arisen Phe-11 interaction with the ligand. In S. purpuratus, hydrophobic contacts between Tyr106, Trp-143, Ala-175 and the ligand are retained. Catalytic site residues Asp-17 and Cys-179 also bind to the ligand through an Hbond and a hydrophobic interaction. Two unique hydrogen bonds (Asp-57 and get Peptide M Leu-174) and hydrophobic contacts (His-109 and Phe-22) arise in the ligand-protein interaction. It can also be noticed that a conserved histidine (His-113 in B. floridae and C. teleta, and His-109 in S. purpuratus) maintains the interaction with the ligand.DiscussionNicotinamide phosphoribosyltransferases (NAMPTs) and nicotinamidases (PNCs) are the main NAD salvage enzymes and, until recently, were thought to occur in distinct lineages. Our data show that several Metazoan species have predicted homologues of both enzymes and that both genes are simultaneously expressed in B. floridae, S. purpuratus, C. teleta and N. vectensis. The distribution of NAMPT and PNC homologues points to the presence of both genes in early eukaryote evolution with selective gene loss andretention in different animal lineages. Interestingly, loss of either one of the genes was predominantly found in fast evolving lineages, namely D. melanogaster, C. elegans and C. intestinalis, while slow-evolving species such as B. floridae retained both [44]. This is also reflected in genome architecture, with conserved NAMPT microsynteny in vertebrates and B. floridae. We also highlight different conservation patterns in NAMPT and PNC homologues, at the protein amino acid sequence and at the 3D structural level. NAMPT sequences are highly conserved, as evidenced by small evolutionary divergences between species and long stretches of identical amino acids surrounding important catalytic and structural positions. As dimerization is required for NAMPT activity [25], in addition to active site residues that interact with the substrates and reaction produc.Binding status of NCA. The three hydrogen bonding interactions (His-113 to NCA oxygen atom, Asp-62 to NCA nitrogen atom and His-113 to Asp-62) sustain the conformational position of the ligand. The Zn2+ keeps the strong binding to the ligand that was also present in L. infantum PNC (PDB 3R2J). In C. teleta the Trp-110 (hydrophobic interaction) and Tyr-147 (H-bond interaction) are the residues from the active site that play an important role in the ligandEvolution of NAMPT and NicotinamidaseFigure 4. Syntenic organization of NAMPT homologues. Gene order and organization are represented for several lineages, and show conservation of microsynteny in chordates. H. sapiens chromosome 7, M. musculus chromosome 12, D. rerio chromosome 4, B. floridae scaffold 633, N. vectensis scaffold 360, T. adhaerens scaffold 2 and M. brevicollis scaffold 7 are displayed and dots indicate intervals containing multiple genes (.4). doi:10.1371/journal.pone.0064674.greceptor interaction. As in B. floridae, the His-113 has a hydrogen bond connection with NCA. Two other H-bond interactions not present in L. infantum PNC (Ser-70 and Lys-108) appear to be important to ligand binding. The interaction between Zn2+ and ligand is maintained. Although no significant changes in ligand conformation were observed, hydrogen bonds in N. vectensis were not predicted. When compared to 3R2J, hydrophobic interactions Cys-21, Trp-99, Ala-169 and Cys-173 are kept for the active site residues. Hydrophobic interactions for the catalytic residue Cys173 are present, as well as a newly arisen Phe-11 interaction with the ligand. In S. purpuratus, hydrophobic contacts between Tyr106, Trp-143, Ala-175 and the ligand are retained. Catalytic site residues Asp-17 and Cys-179 also bind to the ligand through an Hbond and a hydrophobic interaction. Two unique hydrogen bonds (Asp-57 and Leu-174) and hydrophobic contacts (His-109 and Phe-22) arise in the ligand-protein interaction. It can also be noticed that a conserved histidine (His-113 in B. floridae and C. teleta, and His-109 in S. purpuratus) maintains the interaction with the ligand.DiscussionNicotinamide phosphoribosyltransferases (NAMPTs) and nicotinamidases (PNCs) are the main NAD salvage enzymes and, until recently, were thought to occur in distinct lineages. Our data show that several Metazoan species have predicted homologues of both enzymes and that both genes are simultaneously expressed in B. floridae, S. purpuratus, C. teleta and N. vectensis. The distribution of NAMPT and PNC homologues points to the presence of both genes in early eukaryote evolution with selective gene loss andretention in different animal lineages. Interestingly, loss of either one of the genes was predominantly found in fast evolving lineages, namely D. melanogaster, C. elegans and C. intestinalis, while slow-evolving species such as B. floridae retained both [44]. This is also reflected in genome architecture, with conserved NAMPT microsynteny in vertebrates and B. floridae. We also highlight different conservation patterns in NAMPT and PNC homologues, at the protein amino acid sequence and at the 3D structural level. NAMPT sequences are highly conserved, as evidenced by small evolutionary divergences between species and long stretches of identical amino acids surrounding important catalytic and structural positions. As dimerization is required for NAMPT activity [25], in addition to active site residues that interact with the substrates and reaction produc.
