start-ver=1.4 cd-journal=joma no-vol=143 cd-vols= no-issue=4 article-no= start-page=467 end-page=473 dt-received= dt-revised= dt-accepted= dt-pub-year=2008 dt-pub=20080626 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Selenite Assimilation into Formate Dehydrogenase H Depends on Thioredoxin Reductase in Escherichia coli en-subtitle= kn-subtitle= en-abstract= kn-abstract=

Escherichia coli growing under anaerobic conditions produce H-2 and CO2 by the enzymatic cleavage of formate that is produced from pyruvate at the end of glycolysis. Selenium is an integral part of formate dehydrogenase H (FDHH), which catalyses the first step in the formate hydrogen lyase (FHL) system. The genes of FHL system are transcribed only under anaerobic conditions, in the presence of a sigma(54)-dependent transcriptional activator Fh1A that binds formate as an effector molecule. Although the formate addition to the nutrient media has been an established procedure for inducing high FDHH activity, we have identified a low-salt nutrient medium containing <0.1% NaCl enabled constitutive, high expression of FDHH even without formate and D-glucose added to the medium. The novel conditions allowed us to study the effects of disrupting genes like trxB (thioredoxin reductase) or gor (glutathione reductase) on the production of FDHH activity and also reductive assimilation of selenite (SeO32-) into the selenoprotein. Despite the widely accepted hypothesis that selenite is reduced by glutathione reductase-dependent system, it was demonstrated that trxB gene was essential for FDHH production and for labelling the FDHH polypeptide with Se-75-selenite. Our present study reports for the first time the physiological involvement of thioredoxin reductase in the reductive assimilation of selenite in E. coli.

en-copyright= kn-copyright= en-aut-name=TakahataMuneaki en-aut-sei=Takahata en-aut-mei=Muneaki kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=TamuraTakashi en-aut-sei=Tamura en-aut-mei=Takashi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=AbeKatsumasa en-aut-sei=Abe en-aut-mei=Katsumasa kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= en-aut-name=MiharaHisaaki en-aut-sei=Mihara en-aut-mei=Hisaaki kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=4 ORCID= en-aut-name=KurokawaSuguru en-aut-sei=Kurokawa en-aut-mei=Suguru kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=5 ORCID= en-aut-name=YamamotoYoshihiro en-aut-sei=Yamamoto en-aut-mei=Yoshihiro kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=6 ORCID= en-aut-name=NakanoRyuhei en-aut-sei=Nakano en-aut-mei=Ryuhei kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=7 ORCID= en-aut-name=EsakiNobuyoshi en-aut-sei=Esaki en-aut-mei=Nobuyoshi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=8 ORCID= en-aut-name=InagakiKenji en-aut-sei=Inagaki en-aut-mei=Kenji kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=9 ORCID= affil-num=1 en-affil= kn-affil=Department of Biofunctional Chemistry, Graduate School of Natural Science and Technology, Okayama University affil-num=2 en-affil= kn-affil=Department of Biofunctional Chemistry, Graduate School of Natural Science and Technology, Okayama University affil-num=3 en-affil= kn-affil=Laboratory of Molecular Microbial Science, Institute for Chemical Research, Kyoto University affil-num=4 en-affil= kn-affil=Laboratory of Molecular Microbial Science, Institute for Chemical Research, Kyoto University affil-num=5 en-affil= kn-affil=Laboratory of Molecular Microbial Science, Institute for Chemical Research, Kyoto University affil-num=6 en-affil= kn-affil=Department of Genetics, Hyogo College of Medicine affil-num=7 en-affil= kn-affil=Department of Biofunctional Chemistry, Graduate School of Natural Science and Technology, Okayama University affil-num=8 en-affil= kn-affil=Department of Genetics, Hyogo College of Medicine affil-num=9 en-affil= kn-affil=Department of Biofunctional Chemistry, Graduate School of Natural Science and Technology, Okayama University en-keyword=formate dehydrogenase H kn-keyword=formate dehydrogenase H en-keyword=selenite assimilation kn-keyword=selenite assimilation en-keyword=thioredoxin reductase kn-keyword=thioredoxin reductase END