This model describes NadN of Haemophilus influenzae and a small number of close homologs in pathogenic, Gram-negative bacteria. NadN is a periplasmic enzyme that cleaves NAD (nicotinamide adenine dinucleotide) to NMN (nicotinamide mononucleotide) and AMP. The NMN must be converted by a 5'-nucleotidase to nicotinamide riboside for import. NadN belongs a large family of 5'-nucleotidases and has NMN 5'-nucleotidase activity for NMN, AMP, etc. [Transport and binding proteins, Other, Biosynthesis of cofactors, prosthetic groups, and carriers, Pyridine nucleotides]
Jiyao W et al.(2023). "The conserved domain database in 2023.",