InterPro domain: IPR022310

NAD+ synthase ( 6.3.5.1 ) catalyzes the last step in the biosynthesis of nicotinamide adenine dinucleotide and is induced by stress factors such as heat shock and glucose limitation. The three-dimensional structure of NH3-dependent NAD+ synthetase from Bacillus subtilis, in its free form and in complex with ATP shows that the enzyme consists of a tight homodimer with alpha/beta subunit topology [ 1 ].

This domain is also found in guanosine 5'-monophosphate (GMP) synthetase. GMP synthase catalyses the synthesis of GMP from XMP. The protein is a homodimer, but in some archaea it is a heterodimer composed of a glutamine amidotransferase subunit and a ATP pyrophosphatase subunit. In eucaryotes, bacteria, and some archaea the two catalytic units are encoded by a single gene, producing a two-domain-type GMP, with a GATase domain in the N-terminal half and a ATP-PPase domain in the C-terminal half. This entry represents the ATP pyrophosphatase domain.

1. Crystal structure of NH3-dependent NAD+ synthetase from Bacillus subtilis. EMBO J. 15, 5125-34