6gyf

Crystal structure of NadR protein in complex with NR

spinqualitylabelsall models 6gyf, resolution 2.70Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 6gyf is a 2 chain structure with sequence from "streptococcus_hollandicus"_scholl_1891 "streptococcus hollandicus" scholl 1891. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: MG, NMN, SO4 Related: 6gye Gene: NCDO763_1675 ("Streptococcus hollandicus" Scholl 1891) Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Publication Abstract from PubMed NadR is a bifunctional enzyme that converts nicotinamide riboside (NR) into nicotinamide mononucleotide (NMN), which is then converted into nicotinamide adenine dinucleotide (NAD). Although a crystal structure of the enzyme from the Gram-negative bacterium Haemophilus influenzae is known, structural understanding of its catalytic mechanism remains unclear. Here, we purified the NadR enzyme from Lactococcus lactis and established an assay to determine the combined activity of this bifunctional enzyme. The conversion of NR into NAD showed hyperbolic dependence on the NR concentration, but sigmoidal dependence on the ATP concentration. The apparent cooperativity for ATP may be explained because both reactions catalyzed by the bifunctional enzyme (phosphorylation of NR and adenylation of NMN) require ATP. The conversion of NMN into NAD followed simple Michaelis-Menten kinetics for NMN, but again with the sigmoidal dependence on the ATP concentration. In this case, the apparent cooperativity is unexpected since only a single ATP is used in the NMN adenylyltransferase catalyzed reaction. To determine the possible structural determinants of such cooperativity, we solved the crystal structure of NadR from L. lactis (NadRLl). Co-crystallization with NAD, NR, NMN, ATP, and AMP-PNP revealed a 'sink' for adenine nucleotides in a location between two domains. This sink could be a regulatory site, or it may facilitate the channeling of substrates between the two domains. Structural and Functional Characterization of NadR from Lactococcus lactis.,Stetsenko A, Singh R, Jaehme M, Guskov A, Slotboom DJ Molecules. 2020 Apr 22;25(8). pii: molecules25081940. doi:, 10.3390/molecules25081940. PMID:32331317 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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