| Structural highlights
3q3o is a 4 chain structure with sequence from Atcc 25411. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance.
| | Ligands: | , , |
| Related: | 3q14, 3q2a, 3q3m, 3q3n, 3dhh |
| Gene: | Q00456, tmoA (ATCC 25411), Q00460, tmoE (ATCC 25411), Q00457, tmoB (ATCC 25411), Q00459, tmoD (ATCC 25411) |
| Resources: | FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT |
Function
[TMOD_PSEME] Effector protein subunit of the multicomponent enzyme toluene-4-monooxygenase that hydroxylates toluene to form p-cresol. Required for optimal efficiency and specificity of the holoenzyme.[1] [2] [3] [TMOB_PSEME] Subunit T4moB of the multicomponent enzyme toluene-4-monooxygenase that hydroxylates toluene to form p-cresol.[4] [5] [TMOE_PSEME] Subunit of the multicomponent enzyme toluene-4-monooxygenase that hydroxylates toluene to form p-cresol.
Publication Abstract from PubMed
Crystal structures of toluene 4-monooxygenase hydroxylase in complex with reaction products and effector protein reveal active site interactions leading to regiospecificity. Complexes with phenolic products yield an asymmetric mu-phenoxo-bridged diiron center and a shift of diiron ligand E231 into a hydrogen bonding position with conserved T201. In contrast, complexes with inhibitors p-NH(2)-benzoate and p-Br-benzoate showed a mu-1,1 coordination of carboxylate oxygen between the iron atoms and only a partial shift in the position of E231. Among active site residues, F176 trapped the aromatic ring of products against a surface of the active site cavity formed by G103, E104 and A107, while F196 positioned the aromatic ring against this surface via a pi-stacking interaction. The proximity of G103 and F176 to the para substituent of the substrate aromatic ring and the structure of G103L T4moHD suggest how changes in regiospecificity arise from mutations at G103. Although effector protein binding produced significant shifts in the positions of residues along the outer portion of the active site (T201, N202, and Q228) and in some iron ligands (E231 and E197), surprisingly minor shifts (<1 A) were produced in F176, F196, and other interior residues of the active site. Likewise, products bound to the diiron center in either the presence or absence of effector protein did not significantly shift the position of the interior residues, suggesting that positioning of the cognate substrates will not be strongly influenced by effector protein binding. Thus, changes in product distributions in the absence of the effector protein are proposed to arise from differences in rates of chemical steps of the reaction relative to motion of substrates within the active site channel of the uncomplexed, less efficient enzyme, while structural changes in diiron ligand geometry associated with cycling between diferrous and diferric states are discussed for their potential contribution to product release.
Crystallographic Analysis of Active Site Contributions to Regiospecificity in the Diiron Enzyme Toluene 4-Monooxygenase.,Bailey LJ, Acheson JF, McCoy JG, Elsen NL, Phillips GN, Fox BG Biochemistry. 2012 Feb 2. PMID:22264099[6]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
References
- ↑ Hemmi H, Studts JM, Chae YK, Song J, Markley JL, Fox BG. Solution structure of the toluene 4-monooxygenase effector protein (T4moD). Biochemistry. 2001 Mar 27;40(12):3512-24. PMID:11297417
- ↑ Lountos GT, Mitchell KH, Studts JM, Fox BG, Orville AM. Crystal structures and functional studies of T4moD, the toluene 4-monooxygenase catalytic effector protein. Biochemistry. 2005 May 17;44(19):7131-42. PMID:15882052 doi:10.1021/bi047459g
- ↑ Bailey LJ, McCoy JG, Phillips GN Jr, Fox BG. Structural consequences of effector protein complex formation in a diiron hydroxylase. Proc Natl Acad Sci U S A. 2008 Dec 9;105(49):19194-8. Epub 2008 Nov 25. PMID:19033467
- ↑ Elsen NL, Bailey LJ, Hauser AD, Fox BG. Role for threonine 201 in the catalytic cycle of the soluble diiron hydroxylase toluene 4-monooxygenase. Biochemistry. 2009 May 12;48(18):3838-46. PMID:19290655 doi:10.1021/bi900144a
- ↑ Bailey LJ, Fox BG. Crystallographic and catalytic studies of the peroxide-shunt reaction in a diiron hydroxylase. Biochemistry. 2009 Sep 29;48(38):8932-9. PMID:19705873 doi:10.1021/bi901150a
- ↑ Bailey LJ, Acheson JF, McCoy JG, Elsen NL, Phillips GN, Fox BG. Crystallographic Analysis of Active Site Contributions to Regiospecificity in the Diiron Enzyme Toluene 4-Monooxygenase. Biochemistry. 2012 Feb 2. PMID:22264099 doi:10.1021/bi2018333
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