InterPro domain: IPR006405

A deep split separates two related families of proteins, one of which includes experimentally characterised examples of nicotinate phosphoribosyltransferase ( IPR006406 ), the first enzyme of NAD salvage biosynthesis. This entry represents the other family. Members have a different (longer) spacing of several key motifs and have an additional C-terminal domain of up to 100 residues. One argument suggesting that this family represents the same enzyme is that no species has a member of both families. Another is that the gene encoding this protein is located near other NAD salvage biosynthesis genes in Nostoc and in at least four different Gram-positive bacteria. NAD and NADP are ubiquitous in life. Most members of this family are from Gram-positive bacteria. An additional set of mutually closely related archaeal sequences score between the trusted and noise cut-offs.

This entry includes pncB1 and pncB2 from Mycobacterium tuberculosis, which also play a role in NAD salvage synthesis [ 1 ].

1. Biosynthesis and recycling of nicotinamide cofactors in mycobacterium tuberculosis. An essential role for NAD in nonreplicating bacilli. J. Biol. Chem. 283, 19329-41