Butanol production in Clostridium acetobutylicum is controlled by thiolase redox-switch

Butanol production in Clostridium acetobutylicum is controlled by thiolase redox-switch
 

n-Butanol is a valuable biofuel that can be produced industrially by bacterial fermentation.

The authors in the journal Nature Communications uncover a redox-switch within Clostridium acetobutylicum’s thiolase, CaTHL —a key enzyme involved in n-butanol biosynthesis from two acetyl-coenzyme A (CoA) molecules —that controls the rate of fermentative butanol production.

Unlike those from other aerobic bacteria such as Escherichia coli and Zoogloea ramegera, thiolase in Clostridium acetobutylicum is regulated by the redox-switch modulation through reversible disulfide bond formation between two catalytic cysteine residues, Cys88 and Cys378.

When CaTHL is overexpressed in wild-type C. acetobutylicum, butanol production is reduced due to the disturbance of acidogenic to solventogenic shift.

TheCaTHLV77Q/N153Y/A286K mutant, which is not able to form disulfide bonds, exhibits higher activity than wild-type CaTHL, and enhances butanol production upon overexpression.

On the basis of these results, authors suggest that CaTHL functions as a key enzyme in the regulation of the main metabolism of C. acetobutylicum through a redox-switch regulatory mechanism.

http://www.nature.com/ncomms/2015/150922/ncomms9410/full/ncomms9410.html

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