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Please use this identifier to cite or link to this item: http://repository.iitr.ac.in/handle/123456789/26957
Title: Characterization of biphenyl dioxygenase of Pandoraea pnomenusa B-356 as a potent polychlorinated biphenyl-degrading enzyme
Authors: Gómez-Gil L.
Kumar, Pravindra R.Manish
Barriault D.
Bolin J.T.
Sylvestre M.
Eltis L.D.
Published in: Journal of Bacteriology
Abstract: Biphenyl dioxygenase (BPDO) catalyzes the aerobic transformation of biphenyl and various polychlorinated biphenyls (PCBs). In three different assays, BPDOB356 from Pandoraea pnomenusa B-356 was a more potent PCB-degrading enzyme than BPDOLB400 from Burkholderia xenovorans LB400 (75% amino acid sequence identity), transforming nine congeners in the following order of preference: 2,3′,4-trichloro ∼ 2,3,4′- trichloro > 3,3′-dichloro > 2,4,4′-trichloro > 4,4′-dichloro ∼ 2,2′-dichloro > 2,6-dichloro > 2,2′,3,3′-tetrachloro ∼ 2,2′,5,5′-tetrachloro. Except for 2,2′,5,5′-tetrachlorobiphenyl, BPDOB356 transformed each congener at a higher rate than BPDOLB400. The assays used either whole cells or purified enzymes and either individual congeners or mixtures of congeners. Product analyses established previously unrecognized BPDOB356 activities, including the 3,4-dihydroxylation of 2,6-dichlorobiphenyI. BPDOLB400 had a greater apparent specificity for biphenyl than BPDOB356 (kcat/Km = 2.4 × 106 ± 0.7 × 106 M-1 s -1 versus kcat/Km = 0.21 × 106 ± 0.04 × 106 M-1 s-1). However, the latter transformed biphenyl at a higher maximal rate (kcat = 4.1 ± 0.2 s_1 versus kcat = 0.4 ± 0.1 s -1). A variant of BPDOLB400 containing four active site residues of BPDOB356 transformed para-substituted congeners better than BPDOLB400. Interestingly, a substitution remote from the active site, A267S, increased the enzyme's preference for meto-substituted congeners. Moreover, this substitution had a greater effect on the kinetics of biphenyl utilization than substitutions in the substrate-binding pocket. In all variants, the degree of coupling between congener depletion and O2 consumption was approximately proportional to congener depletion. At 2.4-Å resolution, the crystal structure of the BPDOB356-2,6- dichlorobiphenyl complex, the first crystal structure of a BPDO-PCB complex, provided additional insight into the reactivity of this isozyme with this congener, as well as into the differences in congener preferences of the BPDOs. Copyright © 2007, American Society for Microbiology. All Rights Reserved.
Citation: Journal of Bacteriology, 189(15): 5705-5715
URI: https://doi.org/10.1128/JB.01476-06
http://repository.iitr.ac.in/handle/123456789/26957
Issue Date: 2007
Keywords: 2,2',3'3' tetrachlorobiphenyl
2,2'5,5' tetrachlorobiphenyl
2,3',4 trichlorobiphenyl
2,3,4' trichlorobiphenyl
2,4,4' trichlorobiphenyl
2,6 dichlorobiphenyl
3,3' dichlorobiphenyl
3,4 biphenyldiol
4,4' dichlorobiphenyl
biphenyl derivative
biphenyl dioxygenase
dichlorobiphenyl
dioxygenase
enzyme variant
isoenzyme
polychlorinated biphenyl derivative
unclassified drug
aerobic metabolism
amino acid sequence
article
biotransformation
Burkholderia
Burkholderia xenovorans
Comamonas
controlled study
crystal structure
enzyme active site
enzyme activity
enzyme assay
enzyme mechanism
enzyme purification
enzyme specificity
nonhuman
oxygen consumption
Pandoraea pnomenusa
priority journal
Amino Acid Substitution
Biotransformation
Burkholderiaceae
Crystallography, X-Ray
Gas Chromatography-Mass Spectrometry
Iron-Sulfur Proteins
Kinetics
Magnetic Resonance Spectroscopy
Models, Molecular
Oxygenases
Polychlorinated Biphenyls
Protein Structure, Tertiary
Substrate Specificity
Burkholderia xenovorans
Pandoraea pnomenusa
ISSN: 219193
Author Scopus IDs: 18233632900
55064809000
6602879821
57197844041
7005984229
7003863696
Author Affiliations: Gómez-Gil, L., Departments of Microbiology and Biochemistry, Life Sciences Institute, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
Kumar, P., Department of Biological Sciences, Purdue University, West Lafayette, IN, United States
Barriault, D., Institut National de Recherche Scientifique (INRS-Institut Armand-Frappier), Pointe-Claire, Que. H9R 1G6, Canada
Bolin, J.T., Department of Biological Sciences, Purdue University, West Lafayette, IN, United States
Sylvestre, M., Institut National de Recherche Scientifique (INRS-Institut Armand-Frappier), Pointe-Claire, Que. H9R 1G6, Canada
Eltis, L.D., Departments of Microbiology and Biochemistry, Life Sciences Institute, University of British Columbia, Vancouver, BC V6T 1Z3, Canada, University of British Columbia, 2350 Health Sciences Mall, Vancouver, BC V6T 1Z3, Canada
Funding Details: 
Corresponding Author: Eltis, L.D.; University of British Columbia, , Vancouver, BC V6T 1Z3, Canada; email: leltis@interchange.ubc.ca
Appears in Collections:Journal Publications [BT]

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