Cupin Variants as a Macromolecular Ligand Library for Stereoselective Michael Addition of Nitroalkanes

Cupin superfamily proteins (TM1459) work as a macromolecular ligand framework with a double‐stranded β‐barrel structure ligating to a Cu ion through histidine side chains. Variegating the first coordination sphere of TM1459 revealed that H52A and H54A/H58A mutants effectively catalyzed the diastereo‐ and enantioselective Michael addition reaction of nitroalkanes to an α,β‐unsaturated ketone. Moreover, calculated substrate docking signified C106N and F104W single‐point mutations, which inverted the diastereoselectivity of H52A and further improved the stereoselectivity of H54A/H58A, respectively. Die rationale Änderung der ersten und zweiten Koordinationssphäre innerhalb des Cupin‐Proteins führte zu robusten künstlichen Metalloenzymen. Diese Mutanten können die enantio‐ und diastereodivergente Michael‐Additionsreaktion von Nitroalkanen katalysieren.