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Structural and biochemical characterization of gentisate 1,2‐dioxygenase from Escherichia coli O157:H7
Author(s) -
Adams Melanie A.,
Singh Vinay K.,
Keller Bernd O.,
Jia Zongchao
Publication year - 2006
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1111/j.1365-2958.2006.05334.x
Subject(s) - biology , escherichia coli , dioxygenase , enterobacteriaceae , escherichia coli proteins , microbiology and biotechnology , biochemistry , enzyme , gene
Summary Gentisic acid (2,5‐dihydroxybenzoic acid) is a key intermediate in aerobic bacterial pathways that are responsible for the metabolism of a large number of aromatic compounds. The critical step of these pathways is the oxygen‐dependent reaction catalysed by gentisate 1,2‐dioxygenase which opens the aromatic ring of gentisate to form maleylpyruvate. From gentisic acid, the cell derives carbon and energy through the conversion of maleylpyruvate to central metabolites. We have confirmed the annotation of a gentisate 1,2‐dioygenase from the pathogenic O157:H7 Escherichia coli strain and present the first structural characterization of this family of enzymes. The identity of the reaction product was revealed using tandem mass spectroscopy. The operon responsible for the degradation of gentisate in this organism exhibits a high degree of conservation with the gentisate‐degrading operons of other pathogenic bacteria, including the Shiga toxin‐producing E. coli O103:H2, but does not appear to be present in non‐pathogenic strains. The acquisition of the gentisate operon may represent a special adaptation to meet carbon source requirements under conditions of environmental stress and may provide a selective advantage for enterohaemorrhagic E. coli relative to their non‐pathogenic counterparts.