Regulation of active site coupling in glutamine-dependent NAD(+) synthetase

Nat Struct Mol Biol. 2009 Apr;16(4):421-9. doi: 10.1038/nsmb.1567. Epub 2009 Mar 8.


NAD(+) is an essential metabolite both as a cofactor in energy metabolism and redox homeostasis and as a regulator of cellular processes. In contrast to humans, Mycobacterium tuberculosis NAD(+) biosynthesis is absolutely dependent on the activity of a multifunctional glutamine-dependent NAD(+) synthetase, which catalyzes the ATP-dependent formation of NAD(+) at the synthetase domain using ammonia derived from L-glutamine in the glutaminase domain. Here we report the kinetics and structural characterization of M. tuberculosis NAD(+) synthetase. The kinetics data strongly suggest tightly coupled regulation of the catalytic activities. The structure, the first of a glutamine-dependent NAD(+) synthetase, reveals a homooctameric subunit organization suggesting a tight dependence of catalysis on the quaternary structure, a 40-A intersubunit ammonia tunnel and structural elements that may be involved in the transfer of information between catalytic sites.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Amide Synthases / chemistry*
  • Ammonia / metabolism
  • Catalytic Domain*
  • Crystallography, X-Ray
  • Glutamine / metabolism
  • Kinetics
  • Models, Molecular
  • Mycobacterium tuberculosis / enzymology*
  • NAD / metabolism
  • Protein Multimerization
  • Protein Structure, Quaternary
  • Protein Subunits


  • Protein Subunits
  • Glutamine
  • NAD
  • Ammonia
  • Amide Synthases
  • NAD+ synthase

Associated data

  • PDB/3DLA