Reaction mechanism and stereochemistry of gamma-hexachlorocyclohexane dehydrochlorinase LinA

TRANTÍREK, Lukáš, Kamila HYNKOVÁ, Yuji NAGATA, Alexey MURZIN, Alena ANSORGOVÁ, Vladimír SKLENÁŘ and Jiří DAMBORSKÝ. Reaction mechanism and stereochemistry of gamma-hexachlorocyclohexane dehydrochlorinase LinA. Journal of Biological Chemistry. 2001, vol. 276, No 11, p. 7734-7740.

Basic information

• Original name: Reaction mechanism and stereochemistry of gamma-hexachlorocyclohexane dehydrochlorinase LinA
• Authors: TRANTÍREK, Lukáš (203 Czech Republic), Kamila HYNKOVÁ, Yuji NAGATA, Alexey MURZIN, Alena ANSORGOVÁ (203 Czech Republic), Vladimír SKLENÁŘ (203 Czech Republic) and Jiří DAMBORSKÝ (203 Czech Republic).
• Edition: Journal of Biological Chemistry, 2001.

Other information

• Original language: English
• Type of outcome: Article in a journal
• Field of Study: 10600 1.6 Biological sciences
• Country of publisher: United States of America
• Confidentiality degree: is not subject to a state or trade secret
• WWW: URL
• RIV identification code: RIV/00216224:14310/01:00004145
• Organization unit: Faculty of Science
• UT WoS: 000167474900011

Abstract

g-hexachlorocyclohexane dehydrochlorinase (LinA) catalyses the initial steps in the biotransformation of the important insecticide g-hexachlorocyclohexane (g-HCH) by the soil bacterium Sphingomonas paucimobilis UT26. Stereochemical analysis of the reaction products formed during conversion of g-HCH by LinA was investigated by GC-MS, NMR, CD and molecular modeling. The NMR spectra of 1,3,4,5,6-pentachlorocyclohexene (PCCH) produced from g-HCH using either enzymatic dehydrochlorination or alkaline dehydrochlorination were compared and found to be identical. Both enantiomers present in the racemate of synthetic g-PCCH were converted by LinA, each at a different rate. 1,2,4-trichlorobenzene (1,2,4-TCB) was detected as the only product of the biotransformation of biosynthetic g-PCCH. 1,2,4-TCB and 1,2,3-TCB were identified as the dehydrochlorination products of racemic g-PCCH. d-PCCH was detected as the only product of dehydrochlorination of d-HCH. LinA requires the presence of a 1,2-biaxial HCl pair on a substrate molecule. LinA enantiotopologically differentiates two 1,2-biaxial HCl pairs present on g-HCH and gives rise to a single PCCH enantiomer 1,3(R),4(S),5(S),6(R)-PCCH. Furthermore, LinA enantiomerically differentiates 1,3(S),4(R),5(R),6(S)-PCCH and 1,3(R),4(S),5(S),6(R)-PCCH. The proposed mechanism of enzymatic biotransformation of g-HCH to 1,2,4-TCB by LinA consists of two 1,2-anti conformationally dependent dehydrochlorinations followed by 1,4-anti dehydrochlorination.

Links

• GA203/97/P149, research and development project: Name: Studium molekulárních mechanismů biodegradačních reakcí - konstrukce QSBR modelů a proteinové inženýrství dehalogenas

Investor: Czech Science Foundation, Study of the molecular mechanisms of biodegradation reactions - construction of QSBR models and protein engineering of haloalkane dehalogenases

• LN00A016, research and development project: Name: BIOMOLEKULÁRNÍ CENTRUM

Investor: Ministry of Education, Youth and Sports of the CR, Biomolecular Center

• ME 276, research and development project: Name: Racionální re-design mikrobiálních enzymů podílejících se na degradaci toxických organických polutantů

Investor: Ministry of Education, Youth and Sports of the CR, Rational re-design of microbial enzymes involved in degradation of toxic organic pollutants.