Structure of nitrilotriacetate monooxygenase component B from Mycobacterium thermoresistibile

Acta Crystallogr Sect F Struct Biol Cryst Commun. 2011 Sep 1;67(Pt 9):1100-5. doi: 10.1107/S1744309111012541. Epub 2011 Aug 16.


Mycobacterium tuberculosis belongs to a large family of soil bacteria which can degrade a remarkably broad range of organic compounds and utilize them as carbon, nitrogen and energy sources. It has been proposed that a variety of mycobacteria can subsist on alternative carbon sources during latency within an infected human host, with the help of enzymes such as nitrilotriacetate monooxygenase (NTA-Mo). NTA-Mo is a member of a class of enzymes which consist of two components: A and B. While component A has monooxygenase activity and is responsible for the oxidation of the substrate, component B consumes cofactor to generate reduced flavin mononucleotide, which is required for component A activity. NTA-MoB from M. thermoresistibile, a rare but infectious close relative of M. tuberculosis which can thrive at elevated temperatures, has been expressed, purified and crystallized. The 1.6 Å resolution crystal structure of component B of NTA-Mo presented here is one of the first crystal structures determined from the organism M. thermoresistibile. The NTA-MoB crystal structure reveals a homodimer with the characteristic split-barrel motif typical of flavin reductases. Surprisingly, NTA-MoB from M. thermoresistibile contains a C-terminal tail that is highly conserved among mycobacterial orthologs and resides in the active site of the other protomer. Based on the structure, the C-terminal tail may modulate NTA-MoB activity in mycobacteria by blocking the binding of flavins and NADH.

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

  • Amino Acid Sequence
  • Conserved Sequence
  • Mixed Function Oxygenases / chemistry*
  • Models, Molecular
  • Molecular Sequence Data
  • Mycobacterium / enzymology*
  • Protein Structure, Tertiary
  • Sequence Alignment


  • Mixed Function Oxygenases
  • nitrilotriacetate monooxygenase

Associated data

  • PDB/3NFW