Analysis of the role of LinA and LinB in biodegradation of delta-hexachlorocyclohexane.
Commercial formulations of hexachlorocyclohexane (HCH) consist of a mixture of four isomers, alpha, beta, gamma and delta. All these four isomers are toxic and recalcitrant pollutants. Sphingobium (formerly Sphingomonas) sp. strain BHC-A is able to degrade all four HCH isomers. Eight lin genes responsible for the degradation of gamma-HCH in BHC-A were cloned and analysed for their role in the degradation of delta-HCH, and the initial conversion steps in delta-HCH catabolism by LinA and LinB in BHC-A were found. LinA dehydrochlorinated delta-HCH to produce 1,3,4,6-tetrachloro-1,4-cyclohexadiene (1,4-TCDN) via delta-pentachlorocyclohexene (delta-PCCH). Subsequently, both 1,4-TCDN and delta-PCCH are catalysed by LinB via two successive rounds of hydrolytic dechlorinations to form 2,5-dichloro-2,5-cyclohexadiene-1,4-diol (2,5-DDOL) and 2,3,5-trichloro-5-cyclohexene-1,4-diol (2,3,5-TCDL) respectively. LinB could also catalyse the hydrolytic dechlorination of delta-HCH to 2,3,5,6-tetrachloro-1,4-cyclohexanediol (TDOL) via 2,3,4,5,6-pentachlorocyclohexanol (PCHL).
Key Laboratory of Microbiological Engineering Agricultural Environment, Ministry of Agriculture, Department of Microbiology, College of Life Science, Nanjing Agricultural University, 6 Tongwei Road, Nanjing, Jiangsu Province 210095, China.
Jun
J
Wu
Qing
Q
Hong
Yan
Y
Sun
Yuanfan
Y
Hong
Qiuxiang
Q
Yan
Shunpeng
S
Li
D001673:Biodegradation, Environmental; D001556:Hexachlorocyclohexane / Q000737:chemistry / Q000378:metabolism*; D008190:Lyases / Q000235:genetics / Q000378:metabolism*; D053858:Metabolic Networks and Pathways / Q000235:genetics / Q000502:physiology*; D008969:Molecular Sequence Data; D020578:Sphingomonas / Q000201:enzymology / Q000235:genetics / Q000378:metabolism
C086916:delta-hexachlorocyclohexane; D001556:Hexachlorocyclohexane; D008190:Lyases; C019994:dehydrochlorinases