XAS characterization of the active sites of novel intradiol ring‐cleaving dioxygenases: hydroxyquinol and chlorocatechol dioxygenases

Abstract

The intradiol cleaving dioxygenases hydroxyquinol 1,2-dioxygenase (HQ1,2O) from Nocardiodes simplex 3E, chlorocatechol 1,2-dioxygenase (ClC1,2O) from Rhodococcus erythropolis 1CP, and their anaerobic substrate adducts (hydroxyquinol-HQ1,2O and 4-chlorocatechol-ClC1,2O) have been characterized through X-ray absorption spectroscopy. In both enzymes the iron(III) is pentacoordinated and the distance distribution inside the Fe(III) first coordination shell is close to that already found in the extensively characterized protocatechuate 3,4-dioxygenase. The coordination number and the bond lengths are not significantly affected by the substrate binding. Therefore it is confirmed that the displacement of a protein donor upon substrate binding has to be considered a general step valid for all intradiol dioxygenases.z 1998 Federation of European Biochemical Societies.

A redox switch in CopC: An intriguing copper trafficking protein that binds copper(I) and copper(II) at different sites

“…The full, k 3 weighted, EXAFS spectra (17-750 eV above E 0 ) and their Fourier transforms (FT) calculated over the range 3.0-14.0 Å Ϫ1 have been compared with theoretical simulations obtained by using the rapid curved multiple scattering theory implemented in the set of programs EXCURVE9.20 (33). The data analysis was carried out by using published protocols (34,35).…”

Crystal Structure of 4-Chlorocatechol 1,2-Dioxygenase from the Chlorophenol-utilizing Gram-positive Rhodococcus opacus 1CP

“…X-ray absorption measurements on 4-chlorocatechol 1,2-dioxygenase from Rhodococcus opacus (erythropolis) 1CP (Rho 1,2-CCD hereafter) and other intradiol cleaving dioxygenases have provided the first insights into the recognition of different chemical structures by ortho-cleaving dioxygenases (48).…”

Chlorocatechols Substituted at Positions 4 and 5 Are Substrates of the Broad-Spectrum Chlorocatechol 1,2-Dioxygenase of Pseudomonas chlororaphis RW71

“…More detailed structural information deduced from analysis of the crystal structure of catechol 1,2-dioxygenase, and especially of chlorocatechol 1,2-dioxygenase, how-ever, is scarce. X-ray absorption measurements have provided the first insights into the recognition of chemical structures by ortho-cleaving dioxygenases (7). The turnover of different substrates and recognition of key structures are assumed to be modulated through interactions of specific residues of the polypeptide with the substrate, not by the iron-coordinating ligands (7).…”

“…X-ray absorption measurements have provided the first insights into the recognition of chemical structures by ortho-cleaving dioxygenases (7). The turnover of different substrates and recognition of key structures are assumed to be modulated through interactions of specific residues of the polypeptide with the substrate, not by the iron-coordinating ligands (7). The substrate specificities and affinities of hitherto characterized chlorocatechol 1,2-dioxygenases towards (highly) chlorinated catechols differ considerably, although most of these enzymes share relatively high sequence similarities (51).…”