Fujieda, N.; Itoh, S.

Angew. Chem. 2020, 132, 7791-7794, 10.1002/ange.202000129

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.

Mascareñas, J.L.

Angew. Chem. Int. Ed. 2020, 59, 9149-9154, 10.1002/anie.202002032

The generation of catalytically active metalloproteins inside living mammalian cells is a major research challenge at the interface between catalysis and cell biology. Herein we demonstrate that basic domains of bZIP transcription factors, mutated to include two histidine residues at i and i+4 positions, react with palladium(II) sources to generate catalytically active, stapled pallado-miniproteins. The resulting constrained peptides are efficiently internalized into living mammalian cells, where they perform palladium-promoted depropargylation reactions without cellular fixation. Control experiments confirm the requirement of the peptide scaffolding and the palladium staple for attaining the intracellular reactivity.