6sch
NADH-dependent variant of CBADHNADH-dependent variant of CBADH
Structural highlights
FunctionADH_CLOBE Alcohol dehydrogenase with a preference for medium chain secondary alcohols, such as 2-butanol and isopropanol. Has very low activity with primary alcohols, such as ethanol. Under physiological conditions, the enzyme reduces aldehydes and 2-ketones to produce secondary alcohols. Is active with acetaldehyde and propionaldehyde.[1] [2] Publication Abstract from PubMedThe non-natural needs of industrial applications often require new or improved enzymes. The structures and properties of enzymes are difficult to predict or design de novo. Instead, semi-rational approaches mimicking evolution entail diversification of parent enzymes followed by evaluation of isolated variants. Artificial selection pressures coupling desired enzyme properties to cell growth could overcome this key bottleneck, but are usually narrow in scope. Here we show diverse enzymes using the ubiquitous cofactors nicotinamide adenine dinucleotide (NAD) or nicotinamide adenine dinucleotide phosphate (NADP) can substitute for defective NAD regeneration, representing a very broadly-applicable artificial selection. Inactivation of Escherichia coli genes required for anaerobic NAD regeneration causes a conditional growth defect. Cells are rescued by foreign enzymes connected to the metabolic network only via NAD or NADP, but only when their substrates are supplied. Using this principle, alcohol dehydrogenase, imine reductase and nitroreductase variants with desired selectivity modifications, and a high-performing isopropanol metabolic pathway, are isolated from libraries of millions of variants in single-round experiments with typical limited information to guide design. Versatile selective evolutionary pressure using synthetic defect in universal metabolism.,Selles Vidal L, Murray JW, Heap JT Nat Commun. 2021 Nov 25;12(1):6859. doi: 10.1038/s41467-021-27266-9. PMID:34824282[3] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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