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γ-Hexachlorocyclohexane (γ-HCH, also called γ-BHC and lindane) is a halogenated organic insecticide that causes serious environmental problems. The aerobic degradation pathway of γ-HCH was extensively revealed in bacterial strain Sphingobium japonicum (formerly Sphingomonas paucimobilis) UT26. γ-HCH is transformed to 2,5-dichlorohydroquinone through(More)
The number of available genome sequences is increasing, and easy-to-use software that enables efficient comparative analysis is needed. We developed GenomeMatcher, a stand-alone software package for Mac OS X. GenomeMatcher executes BLAST and MUMmer, and the detected similarities are displayed in two-dimensional and parallel views with similarity values(More)
Polychlorinated biphenyls (PCBs) are serious environmental pollutants that threaten both the natural ecosystem and human health. For remediation of environments contaminated with PCBs, several approaches that exploit the potential of microbes to degrade PCBs have been developed. These approaches include improvement of PCB solubilization and entry into the(More)
The complete genome sequencing of a γ-hexachlorocyclohexane-degrading strain, Sphingobium japonicum UT26, revealed that the genome consists of two circular chromosomes [with sizes of 3.5 Mb (Chr1) and 682kb (Chr2)], a 191-kb large plasmid (pCHQ1), and two small plasmids with sizes of 32 and 5kb. The lin genes are dispersed on Chr1, Chr2, and pCHQ1.(More)
Structural comparison of three different haloalkane dehalogenases suggested that substrate specificity of these bacterial enzymes could be significantly influenced by the size and shape of their entrance tunnels. The surface residue leucine 177 positioned at the tunnel opening of the haloalkane dehalogenase from Sphingomonas paucimobilis UT26 was selected(More)
Enzymes are widely used for the synthesis of pharmaceuticals, agrochemicals, and food additives because they can catalyze enantioselective transformations. Understanding the molecular basis of enzyme–substrate interactions that contribute to enantioselectivity is important for constructing selective enzymes by protein engineering. Up to now, emphasis has(More)
Beta-Hexachlorocyclohexane (beta-HCH) is the most recalcitrant among the alpha-, beta-, gamma-, and delta-isomers of HCH and causes serious environmental pollution problems. We demonstrate here that the haloalkane dehalogenase LinB, reported earlier to mediate the second step in the degradation of gamma-HCH in Sphingomonas paucimobilis UT26, metabolizes(More)
Sphingomonas paucimobilis UT26 utilizes gamma-hexachlorocyclohexane (gamma-HCH) as a sole source of carbon and energy. In our previous study, we cloned and characterized genes that are involved in the conversion of gamma-HCH to maleylacetate (MA) via chlorohydroquinone (CHQ) in UT26. In this study, we identified and characterized an MA reductase gene,(More)
Engineering enzymes to degrade anthropogenic compounds efficiently is challenging. We obtained Rhodococcus rhodochrous haloalkane dehalogenase mutants with up to 32-fold higher activity than wild type toward the toxic, recalcitrant anthropogenic compound 1,2,3-trichloropropane (TCP) using a new strategy. We identified key residues in access tunnels(More)