2NOX

Crystal structure of tryptophan 2,3-dioxygenase from Ralstonia metallidurans

Summary for 2NOX

• Entry DOI: 10.2210/pdb2nox/pdb
• Descriptor: Tryptophan 2,3-dioxygenase, PROTOPORPHYRIN IX CONTAINING FE (3 entities in total)
• Functional Keywords: helical bundle, heme protein, oxidoreductase
• Biological source: Cupriavidus metallidurans
• Total number of polymer chains: 16
• Total formula weight: 530548.32

Authors

Zhang, Y.,Kang, S.A.,Mukherjee, T.,Bale, S.,Crane, B.R.,Begley, T.P.,Ealick, S.E. (deposition date: 2006-10-26, release date: 2006-12-19, Last modification date: 2023-08-30)

Primary citation

Zhang, Y.,Kang, S.A.,Mukherjee, T.,Bale, S.,Crane, B.R.,Begley, T.P.,Ealick, S.E.
Crystal structure and mechanism of tryptophan 2,3-dioxygenase, a heme enzyme involved in tryptophan catabolism and in quinolinate biosynthesis.
Biochemistry, 46:145-155, 2007

PubMed Abstract: The structure of tryptophan 2,3-dioxygenase (TDO) from Ralstonia metallidurans was determined at 2.4 A. TDO catalyzes the irreversible oxidation of l-tryptophan to N-formyl kynurenine, which is the initial step in tryptophan catabolism. TDO is a heme-containing enzyme and is highly specific for its substrate l-tryptophan. The structure is a tetramer with a heme cofactor bound at each active site. The monomeric fold, as well as the heme binding site, is similar to that of the large domain of indoleamine 2,3-dioxygenase, an enzyme that catalyzes the same reaction except with a broader substrate tolerance. Modeling of the putative (S)-tryptophan hydroperoxide intermediate into the active site, as well as substrate analogue and mutagenesis studies, are consistent with a Criegee mechanism for the reaction.

PubMed: 17198384
DOI: 10.1021/bi0620095

Experimental method

X-RAY DIFFRACTION (2.4 Å)