Old yellow enzyme-catalyzed desymmetrizing desaturation

Area of Science:

• Biocatalysis
• Enzyme Engineering
• Organic Synthesis

Background:

• Flavin-dependent old yellow enzymes (OYEs) are established biocatalysts for stereoselective anti-hydrogenations.
• OYEs exhibit catalytic promiscuity, enabling new radical transformations via protein engineering.
• Traditional desaturation methods often require harsh conditions and lack stereochemical control.

Purpose of the Study:

• To repurpose OYEs for asymmetric carbonyl desaturation by inverting their native activity.
• To develop a GkOYE-based system for desymmetrizing cyclohexanones.
• To address limitations of existing desaturation approaches.

Main Methods:

• Directed evolution of an OYE from Geobacillus kaustophilus (GkOYE).
• High-throughput enzyme engineering and protein expression.
• Development of analytical and scalable reaction setups.

Main Results:

• Achieved desymmetrizing desaturation of diverse cyclohexanones using engineered GkOYE.
• Synthesized cyclohexenones with a remote quaternary stereogenic center.
• Demonstrated excellent stereoselectivity under mild reaction conditions.

Conclusions:

• The engineered GkOYE system provides a novel approach for asymmetric carbonyl desaturation.
• This work offers a roadmap for adapting OYEs to challenging desaturative transformations.
• The developed system overcomes limitations of traditional desaturation methods.