[1] Close PnuC homologues are found in a wide range of Gram-negative and Gram-positive bacteria, archaea and eukaryotes.
[7][8] NadR represents a multifunctional regulator/enzyme complex able to integrate several functions, such as enzymatic catalysis, transport, and transcriptional regulatory activities.
Merdanovic et al. characterized two enzymes, an outer membrane nucleotide phosphatase, and an NAD+ nucleotidase (NadN) located in the periplasm.
The study of Merdanovic et al. suggests that the RNK activity of NadR determines NR transport and is negatively regulated by cytoplasmic NAD+ feedback inhibition.
PnuC of Salmonella typhimurium and Haemophilus influenzae are integral membrane proteins, 239 and 226 amino acyl residues (aas) in length, respectively, with 7 putative transmembrane α-helical segments.
PnuC has been shown to resemble SWEET porters in overall fold,[18] supporting the conclusion that these two families are members of the TOG superfamily.