Novel pathway for conversion of chlorohydroxyquinol to maleylacetate in Burkholderia cepacia AC1100.
Burkholderia cepacia AC1100 metabolizes 2,4,5-trichlorophenoxyacetic acid (2,4,5-T) via formation of 5-chlorohydroxyquinol (5-CHQ), hydroxyquinol (HQ), maleylacetate, and beta-oxoadipate. The step(s) leading to the dechlorination of 5-CHQ to HQ has remained unidentified. We demonstrate that a dechlorinating enzyme, TftG, catalyzes the conversion of 5-CHQ to hydroxybenzoquinone, which is then reduced to HQ by a hydroxybenzoquinone reductase (HBQ reductase). HQ is subsequently converted to maleylacetate by hydroxyquinol 1,2-dioxygenase (HQDO). All three enzymes were purified. We demonstrate specific product formation by colorimetric assay and mass spectrometry when 5-CHQ is treated successively with the three enzymes: TftG, TftG plus HBQ reductase, and TftG plus HBQ reductase plus HQDO. This study delineates the complete enzymatic pathway for the degradation of 5-CHQ to maleylacetate.
Department of Microbiology and Immunology, College of Medicine, University of Illinois at Chicago, Chicago, Illinois 60612, USA.
O
O
Zaborina
D L
DL
Daubaras
A
A
Zago
L
L
Xun
K
K
Saido
T
T
Klem
D
D
Nikolic
A M
AM
Chakrabarty
D001426:Bacterial Proteins; D001483:Base Sequence; D016956:Burkholderia cepacia / Q000201:enzymology / Q000378:metabolism*; D002851:Chromatography, High Pressure Liquid; D003001:Cloning, Molecular; D003124:Colorimetry; D017931:DNA Primers; D006873:Hydroquinones / Q000378:metabolism*; D008190:Lyases / Q000302:isolation & purification / Q000378:metabolism*; D008298:Maleates / Q000378:metabolism*; D013058:Mass Spectrometry
C114351:5-chlorohydroxyquinol; D001426:Bacterial Proteins; D017931:DNA Primers; D006873:Hydroquinones; D008298:Maleates; C011905:maleoylacetic acid; D008190:Lyases; C114350:TftG protein, Burkholderia cepacia