2007 Fiscal Year Final Research Report Summary
Molecular Bases of dehalorespiration in strictly anerobic bacteria
| Project/Area Number |
17380055
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Applied microbiology
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| Research Institution | Beppu University (2007)
Kyushu University (2005-2006) |
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Principal Investigator |
FURUKAWA Kensuke Beppu University, Faculty of Food Science and Nutrition, professor (90221556)
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| Co-Investigator(Kenkyū-buntansha) |
GOTO Masatoshi Kyushu University, Department of Bioscience and Biotechnology, Assistant professor (90274521)
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| Project Period (FY) |
2005 – 2007
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| Keywords | strictly anaerobe / dechlorination / dehalorespiration / Desulfitobacterium |
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| Research Abstract |
In this study we have attempted to reveal the mechanism of halorespiration of strictly anaerobic bacterium, Desulfitobacterium hafniense strain Y51 which can dechlorinate voratile highly chlorinated pollutants, tetrachloroethene (PCE) and trichloroethene, to cis-dichloroethene. Strain Y51 can grow through this dehalorepiration process coupled with energy reservation. We have first cloned the pceABCT gene cluster. This gene duster was sandwiched by two nearly identical insertional sequence (IS) to form a composite transposon. PCE dehalogenase encoded by pceA was considered to associate with a membrane anchor. protein encoded by pceB. Immunoprecipitation analysis revealed that the PceT encoded by pceT specifically binds to the precursor PceA, but not to the mature PceA, suggesting that PceT act as a chaperone to fold precursor PceA before being transported to periplasm by Tat system.
The growth of strain Y51 was inhibited by chloroform at as low as 1 M. After prolonged lag time, a mutant strain termed LD which lost the entire pce gene cluster was highly generated. Interestingly, strain LD grew normally in the presence of chloroform even at 10μM. Biochemical and molecular analyses suggested that chloroform inhibit the electron transport system of fumarate respiration in wild type strain Y51 by binding with colinoid, a cofactor of PceA.
The detailed molecular mechanism of dehalorespiration in strictly anaerobic bacteria remained to be elucidated. Further work will be focused on development of the host-vector system in. strictly anaerobic bacteria along with the development of heterologous expression systems of these dehalorespiration genes.
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