| Structural highlights
Function
T23O_XANCP Catalyzes the oxidative cleavage of the L-tryptophan (L-Trp) pyrrole ring.[HAMAP-Rule:MF_01972][1] [2]
Evolutionary Conservation
Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf.
Publication Abstract from PubMed
Tryptophan 2,3-dioxygenase (TDO) and indoleamine 2,3-dioxygenase (IDO) constitute an important, yet relatively poorly understood, family of heme-containing enzymes. Here, we report extensive structural and biochemical studies of the Xanthomonas campestris TDO and a related protein SO4414 from Shewanella oneidensis, including the structure at 1.6-A resolution of the catalytically active, ferrous form of TDO in a binary complex with the substrate L-Trp. The carboxylate and ammonium moieties of tryptophan are recognized by electrostatic and hydrogen-bonding interactions with the enzyme and a propionate group of the heme, thus defining the L-stereospecificity. A second, possibly allosteric, L-Trp-binding site is present at the tetramer interface. The sixth coordination site of the heme-iron is vacant, providing a dioxygen-binding site that would also involve interactions with the ammonium moiety of L-Trp and the amide nitrogen of a glycine residue. The indole ring is positioned correctly for oxygenation at the C2 and C3 atoms. The active site is fully formed only in the binary complex, and biochemical experiments confirm this induced-fit behavior of the enzyme. The active site is completely devoid of water during catalysis, which is supported by our electrochemical studies showing significant stabilization of the enzyme upon substrate binding.
Molecular insights into substrate recognition and catalysis by tryptophan 2,3-dioxygenase.,Forouhar F, Anderson JL, Mowat CG, Vorobiev SM, Hussain A, Abashidze M, Bruckmann C, Thackray SJ, Seetharaman J, Tucker T, Xiao R, Ma LC, Zhao L, Acton TB, Montelione GT, Chapman SK, Tong L Proc Natl Acad Sci U S A. 2007 Jan 9;104(2):473-8. Epub 2006 Dec 29. PMID:17197414[3]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
See Also
References
- ↑ Forouhar F, Anderson JL, Mowat CG, Vorobiev SM, Hussain A, Abashidze M, Bruckmann C, Thackray SJ, Seetharaman J, Tucker T, Xiao R, Ma LC, Zhao L, Acton TB, Montelione GT, Chapman SK, Tong L. Molecular insights into substrate recognition and catalysis by tryptophan 2,3-dioxygenase. Proc Natl Acad Sci U S A. 2007 Jan 9;104(2):473-8. Epub 2006 Dec 29. PMID:17197414
- ↑ Thackray SJ, Bruckmann C, Anderson JL, Campbell LP, Xiao R, Zhao L, Mowat CG, Forouhar F, Tong L, Chapman SK. Histidine 55 of tryptophan 2,3-dioxygenase is not an active site base but regulates catalysis by controlling substrate binding. Biochemistry. 2008 Oct 7;47(40):10677-84. Epub 2008 Sep 11. PMID:18783250 doi:10.1021/bi801202a
- ↑ Forouhar F, Anderson JL, Mowat CG, Vorobiev SM, Hussain A, Abashidze M, Bruckmann C, Thackray SJ, Seetharaman J, Tucker T, Xiao R, Ma LC, Zhao L, Acton TB, Montelione GT, Chapman SK, Tong L. Molecular insights into substrate recognition and catalysis by tryptophan 2,3-dioxygenase. Proc Natl Acad Sci U S A. 2007 Jan 9;104(2):473-8. Epub 2006 Dec 29. PMID:17197414
|