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==Overview== | ==Overview== | ||
The crystal structure of the 3-chlorocatechol 1,2-dioxygenase from the | The crystal structure of the 3-chlorocatechol 1,2-dioxygenase from the Gram-positive bacterium Rhodococcus opacus (erythropolis) 1CP, a Fe(III) ion-containing enzyme specialized in the aerobic biodegradation of 3-chloro- and methyl-substituted catechols, has been solved by molecular replacement techniques using the coordinates of 4-chlorocatechol 1,2-dioxygenase from the same organism (PDB code 1S9A) as a starting model and refined at 1.9 A resolution (R(free) 21.9%; R-factor 17.4%). The analysis of the structure and of the kinetic parameters for a series of different substrates, and the comparison with the corresponding data for the 4-chlorocatechol 1,2-dioxygenase isolated from the same bacterial strain, provides evidence of which active site residues are responsible for the observed differences in substrate specificity. Among the amino acid residues expected to interact with substrates, only three are altered Val53(Ala53), Tyr78(Phe78) and Ala221(Cys224) (3-chlorocatechol 1,2-dioxygenase(4-chlorocatechol 1,2-dioxygenase)), clearly identifying the substitutions influencing substrate selectivity in these enzymes. The crystallographic asymmetric unit contains eight subunits (corresponding to four dimers) that show heterogeneity in the conformation of a co-crystallized molecule bound to the catalytic non-heme iron(III) ion resembling a benzohydroxamate moiety, probably a result of the breakdown of recently discovered siderophores synthesized by Gram-positive bacteria. Several different modes of binding benzohydroxamate into the active site induce distinct conformations of the interacting protein ligands Tyr167 and Arg188, illustrating the plasticity of the active site origin of the more promiscuous substrate preferences of the present enzyme. | ||
==About this Structure== | ==About this Structure== | ||
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[[Category: Briganti, F.]] | [[Category: Briganti, F.]] | ||
[[Category: Ferraroni, M.]] | [[Category: Ferraroni, M.]] | ||
[[Category: Golovleva, L | [[Category: Golovleva, L A.]] | ||
[[Category: Kolomytseva, M | [[Category: Kolomytseva, M P.]] | ||
[[Category: Scozzafava, A.]] | [[Category: Scozzafava, A.]] | ||
[[Category: Solyanikova, I | [[Category: Solyanikova, I P.]] | ||
[[Category: BHO]] | [[Category: BHO]] | ||
[[Category: FE]] | [[Category: FE]] | ||
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[[Category: oxidoreductase]] | [[Category: oxidoreductase]] | ||
''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 16:40:08 2008'' | ||
Revision as of 17:40, 21 February 2008
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CRYSTAL STRUCTURE OF 3-CHLOROCATECHOL 1,2-DIOXYGENASE FROM RHODOCOCCUS OPACUS 1CP
OverviewOverview
The crystal structure of the 3-chlorocatechol 1,2-dioxygenase from the Gram-positive bacterium Rhodococcus opacus (erythropolis) 1CP, a Fe(III) ion-containing enzyme specialized in the aerobic biodegradation of 3-chloro- and methyl-substituted catechols, has been solved by molecular replacement techniques using the coordinates of 4-chlorocatechol 1,2-dioxygenase from the same organism (PDB code 1S9A) as a starting model and refined at 1.9 A resolution (R(free) 21.9%; R-factor 17.4%). The analysis of the structure and of the kinetic parameters for a series of different substrates, and the comparison with the corresponding data for the 4-chlorocatechol 1,2-dioxygenase isolated from the same bacterial strain, provides evidence of which active site residues are responsible for the observed differences in substrate specificity. Among the amino acid residues expected to interact with substrates, only three are altered Val53(Ala53), Tyr78(Phe78) and Ala221(Cys224) (3-chlorocatechol 1,2-dioxygenase(4-chlorocatechol 1,2-dioxygenase)), clearly identifying the substitutions influencing substrate selectivity in these enzymes. The crystallographic asymmetric unit contains eight subunits (corresponding to four dimers) that show heterogeneity in the conformation of a co-crystallized molecule bound to the catalytic non-heme iron(III) ion resembling a benzohydroxamate moiety, probably a result of the breakdown of recently discovered siderophores synthesized by Gram-positive bacteria. Several different modes of binding benzohydroxamate into the active site induce distinct conformations of the interacting protein ligands Tyr167 and Arg188, illustrating the plasticity of the active site origin of the more promiscuous substrate preferences of the present enzyme.
About this StructureAbout this Structure
2BOY is a Single protein structure of sequence from Rhodococcus opacus with , , and as ligands. Active as Catechol 1,2-dioxygenase, with EC number 1.13.11.1 Known structural/functional Site: . Full crystallographic information is available from OCA.
ReferenceReference
Crystal structure of 3-chlorocatechol 1,2-dioxygenase key enzyme of a new modified ortho-pathway from the Gram-positive Rhodococcus opacus 1CP grown on 2-chlorophenol., Ferraroni M, Kolomytseva MP, Solyanikova IP, Scozzafava A, Golovleva LA, Briganti F, J Mol Biol. 2006 Jul 21;360(4):788-99. Epub 2006 Jun 5. PMID:16793061
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