Glutamine-dependent NAD(+) synthetase (IPR014445)

Short name: Gln-dep_NAD_synthase

Overlapping homologous superfamilies

Family relationships


This group represents the glutamine-dependent NAD(+) synthetases with the GAT domain from archaea, bacteria to humans.

NAD+ is involved electron transport and redox reactions and in DNA ligation and protein ADP-ribosylation. In yeast and most other organisms, NAD is generated through the de novo pathway and the salvage pathway. In the de novo pathway, quinolinic acid is converted to nicotinic acid mononucleotide (NaMN). In the salvage pathway, NaMN is generated by recycling of nicotinamide. Both pathways converge on NaMN, which is then converted into deamido-NAD+. Subsequently, deamido-NAD+ is converted to NAD+ by NAD+ synthetase [PMID: 12898714].

NAD+ synthetase has been extensively studied in bacteria. It is encoded by nadE gene in E. coli and by outB gene in B. subtilis [PMID: 7890752]. However, these enzymes are ammonia-dependent (containing an ammonia-utilising domain) and are not included in this entry [PMID: 12771147]. The pokaryotic proteins in this family, such as that from Mycobacterium tuberculosis, contain a nitrilase-related domain, are glutamine-dependent and are included in this entry [PMID: 12771147].

Eukaryotic NAD+ synthetases are glutamine-dependent. In budding yeast, this enzyme is named as Qns1. It contains an N-terminal nitrilase-related domain (contaiing the nitrilase-related active-site residues) and a C-terminal NAD+ synthetase domain [PMID: 12771147]. Both domains are required for its function in vivo. The nitrilase-related domain is the fourth independently evolved glutamine amidotransferase domain to have been identified in nature [PMID: 12771147].

GO terms

Biological Process

GO:0009435 NAD biosynthetic process

Molecular Function

GO:0005524 ATP binding
GO:0003952 NAD+ synthase (glutamine-hydrolyzing) activity

Cellular Component

No terms assigned in this category.

Contributing signatures

Signatures from InterPro member databases are used to construct an entry.