Cloning, functional expression and characterization of a bifunctional 3-hydroxybutanal dehydrogenase /reductase involved in acetone metabolism by Desulfococcus biacutus

BMC Microbiology

Research Article

Hendrik Rusche¹  David Schleheck¹  Bernhard Schink¹  Jasmin Frey¹ 

[1] Department of Biology, University of Konstanz, Postbox 649, D-78457, Konstanz, Germany;

关键词: Acetone activation;    Sulfate-reducing bacteria;    Carbonylation;    Bifunctional MDR superfamily oxidoreductase;   

DOI  :  10.1186/s12866-016-0899-9

 received in 2016-07-29, accepted in 2016-11-17,  发布年份 2016

来源: Springer

【 摘 要 】

BackgroundThe strictly anaerobic, sulfate-reducing bacterium Desulfococcus biacutus can utilize acetone as sole carbon and energy source for growth. Whereas in aerobic and nitrate-reducing bacteria acetone is activated by carboxylation with CO2 to acetoacetate, D. biacutus involves CO as a cosubstrate for acetone activation through a different, so far unknown pathway. Proteomic studies indicated that, among others, a predicted medium-chain dehydrogenase/reductase (MDR) superfamily, zinc-dependent alcohol dehydrogenase (locus tag DebiaDRAFT_04514) is specifically and highly produced during growth with acetone.ResultsThe MDR gene DebiaDRAFT_04514 was cloned and overexpressed in E. coli. The purified recombinant protein required zinc as cofactor, and accepted NADH/NAD+ but not NADPH/NADP+ as electron donor/acceptor. The pH optimum was at pH 8, and the temperature optimum at 45 °C. Highest specific activities were observed for reduction of C3 - C5-aldehydes with NADH, such as propanal to propanol (380 ± 15 mU mg−1 protein), butanal to butanol (300 ± 24 mU mg−1), and 3-hydroxybutanal to 1,3-butanediol (248 ± 60 mU mg−1), however, the enzyme also oxidized 3-hydroxybutanal with NAD+ to acetoacetaldehyde (83 ± 18 mU mg−1).ConclusionThe enzyme might play a key role in acetone degradation by D. biacutus, for example as a bifunctional 3-hydroxybutanal dehydrogenase/reductase. Its recombinant production may represent an important step in the elucidation of the complete degradation pathway.

【 授权许可】

CC BY   
© The Author(s). 2016