Catalyzes the final step of the nicotinamide adenine dinucleotide (NAD) de novo synthesis pathway, the ATP-dependent amidation of deamido-NAD using L-glutamine as a nitrogen source. ATP + deamido-NAD(+) + H2O + L-glutamine = AMP + diphosphate + H(+) + L-glutamate + NAD(+) Cofactor biosynthesis; NAD(+) biosynthesis; NAD(+) from deamido-NAD(+) (L-Gln route): step 1/1. Homohexamer. In the C-terminal section; belongs to the NAD synthetase family.