scholarly journals Deracemization and Stereoinversion of Alcohols Using Two Mutants of Secondary Alcohol Dehydrogenase from Thermoanaerobacter pseudoethanolicus

2020 ◽  
Vol 2020 (30) ◽  
pp. 4750-4754 ◽  
Author(s):  
Sodiq A. Nafiu ◽  
Masateru Takahashi ◽  
Etsuko Takahashi ◽  
Samir M. Hamdan ◽  
Musa M. Musa
Keyword(s):  
Alcohol Dehydrogenase ◽  
Secondary Alcohol ◽  
Secondary Alcohol Dehydrogenase

Cofactor specificity engineering of a long-chain secondary alcohol dehydrogenase from Micrococcus luteus for redox-neutral biotransformation of fatty acids

2019 ◽  
Vol 55 (96) ◽  
pp. 14462-14465 ◽  
Author(s):  
Eun-Ji Seo ◽  
Hye-Ji Kim ◽  
Myeong-Ju Kim ◽  
Jeong-Sun Kim ◽  
Jin-Byung Park
Keyword(s):  
Fatty Acids ◽  
Alcohol Dehydrogenase ◽  
Micrococcus Luteus ◽  
Secondary Alcohol ◽  
Cofactor Specificity ◽  
Secondary Alcohol Dehydrogenase ◽  
Long Chain

Structure-based cofactor specificity engineering of an alcohol dehydrogenase (mLSADH) enables a redox-neutral biotransformation of C18 fatty acids into C9 fatty acids.

scholarly journals Reconstruction of an Acetogenic 2,3-Butanediol Pathway Involving a Novel NADPH-Dependent Primary-Secondary Alcohol Dehydrogenase

2014 ◽  
Vol 80 (11) ◽  
pp. 3394-3403 ◽  
Author(s):  
Michael Köpke ◽  
Monica L. Gerth ◽  
Danielle J. Maddock ◽  
Alexander P. Mueller ◽  
FungMin Liew ◽  
...  
Keyword(s):  
Alcohol Dehydrogenase ◽  
Secondary Alcohol ◽  
Acetolactate Synthase ◽  
Chemical Production ◽  
Content Type ◽  
E Coli ◽  
Gas Fermentation ◽  
Secondary Alcohol Dehydrogenase ◽  
Clostridium Autoethanogenum ◽  
Butanediol Dehydrogenase

ABSTRACTAcetogenic bacteria use CO and/or CO2plus H2as their sole carbon and energy sources. Fermentation processes with these organisms hold promise for producing chemicals and biofuels from abundant waste gas feedstocks while simultaneously reducing industrial greenhouse gas emissions. The acetogenClostridium autoethanogenumis known to synthesize the pyruvate-derived metabolites lactate and 2,3-butanediol during gas fermentation. Industrially, 2,3-butanediol is valuable for chemical production. Here we identify and characterize theC. autoethanogenumenzymes for lactate and 2,3-butanediol biosynthesis. The putativeC. autoethanogenumlactate dehydrogenase was active when expressed inEscherichia coli. The 2,3-butanediol pathway was reconstituted inE. coliby cloning and expressing the candidate genes for acetolactate synthase, acetolactate decarboxylase, and 2,3-butanediol dehydrogenase. Under anaerobic conditions, the resultingE. colistrain produced 1.1 ± 0.2 mM 2R,3R-butanediol (23 μM h−1optical density unit−1), which is comparable to the level produced byC. autoethanogenumduring growth on CO-containing waste gases. In addition to the 2,3-butanediol dehydrogenase, we identified a strictly NADPH-dependent primary-secondary alcohol dehydrogenase (CaADH) that could reduce acetoin to 2,3-butanediol. Detailed kinetic analysis revealed that CaADH accepts a range of 2-, 3-, and 4-carbon substrates, including the nonphysiological ketones acetone and butanone. The high activity of CaADH toward acetone led us to predict, and confirm experimentally, thatC. autoethanogenumcan act as a whole-cell biocatalyst for converting exogenous acetone to isopropanol. Together, our results functionally validate the 2,3-butanediol pathway fromC. autoethanogenum, identify CaADH as a target for further engineering, and demonstrate the potential ofC. autoethanogenumas a platform for sustainable chemical production.

scholarly journals Cloning and expression of the gene encoding the Thermoanaerobacter ethanolicus 39E secondary-alcohol dehydrogenase and biochemical characterization of the enzyme

1996 ◽  
Vol 316 (1) ◽  
pp. 115-122 ◽  
Author(s):  
Douglas S. BURDETTE ◽  
Claire VIEILLE ◽  
J. Gregory ZEIKUS
Keyword(s):  
Alcohol Dehydrogenase ◽  
Secondary Alcohol ◽  
Primary Alcohol ◽  
Recombinant Enzyme ◽  
Amino Acid Sequences ◽  
Cloning And Expression ◽  
Gene Encoding ◽  
Arrhenius Plots ◽  
Thermoanaerobacter Ethanolicus ◽  
Secondary Alcohol Dehydrogenase

The adhB gene encoding Thermoanaerobacter ethanolicus 39E secondary-alcohol dehydrogenase (S-ADH) was cloned, sequenced and expressed in Escherichia coli. The 1056 bp gene encodes a homotetrameric recombinant enzyme consisting of 37.7 kDa subunits. The purified recombinant enzyme is optimally active above 90 °C with a half-life of approx. 1.7 h at 90 °C. An NADP(H)-dependent enzyme, the recombinant S-ADH has 1400-fold greater catalytic efficiency in propan-2-ol oxidation than in ethanol oxidation. The enzyme was inactivated by chemical modification with dithionitrobenzoate (DTNB) and diethylpyrocarbonate, indicating that Cys and His residues are involved in catalysis. Zinc was the only metal enhancing S-ADH reactivation after DTNB modification, implicating the involvement of bound zinc in catalysis. Arrhenius plots for the oxidation of propan-2-ol by the native and recombinant S-ADHs were linear from 25 to 90 °C when the enzymes were incubated at 55 °C before assay. Discontinuities in the Arrhenius plots for propan-2-ol and ethanol oxidations were observed, however, when the enzymes were preincubated at 0 or 25 °C. The observed Arrhenius discontinuity therefore resulted from a temperature-dependent, catalytically significant S-ADH structural change. Hydrophobic cluster analysis comparisons of both mesophilic and thermophilic S-ADH and primary- versus S-ADH amino acid sequences were performed. These comparisons predicted that specific proline residues might contribute to S-ADH thermostability and thermophilicity, and that the catalytic Zn ligands are different in primary-alcohol dehydrogenases (two Cys and a His) and S-ADHs (Cys, His, and Asp).

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