Sprecher
Beschreibung
A major challenge in biocatalysis is the development of novel enzymes for chemical reactions beyond nature’s synthetic repertoire. A successful strategy employs artificial metalloenzymes, which are designed rationally to combine the catalytic properties of a metal cofactor with the chiral environment of a protein scaffold that provides stereoselectivity (1). These systems are genetically encodable and therefore amenable to optimization by directed evolution. This technique mimics natural selection in the laboratory through iterative cycles of mutagenesis and screening (2).
We recently developed a de novo protein scaffold with femtomolar affinity for lanthanides, where metal binding can be observed by sensitizing the element-specific luminescence (3). Lanthanide ions are not only potent Lewis acid catalysts; one of them, cerium(III/IV), also promotes photoredox chemistry. The metal ions are incorporated by dative anchoring, which exploits direct coordination by natural amino acids of the protein. We now work on turning these de novo metalloproteins into a biocatalytic platform for synthetically valuable reactions. Furthermore, we aim to study smaller de novo metallopeptides in the context of prebiotic catalysis by evolving them to drive challenging transformations in metabolic reaction cycles.
References:
(1) Schwizer, F.; Okamoto, Y.; Heinisch, T.; Gu, Y.; Pellizzoni, M. M.; Lebrun, V.; Reuter, R.; Kohler, V.; Lewis, J. C.; Ward, T. R. Artificial Metalloenzymes: Reaction Scope and Optimization Strategies. Chem. Rev. 2018, 118, 142-231.
(2) Zeymer, C.; Hilvert, D. Directed Evolution of Protein Catalysts. Annu. Rev. Biochem. 2018, 87, 131-157.
(3) Caldwell, S. J.; Haydon, I. C.; Piperidou, N.; Huang, P. S.; Bick, M. J.; Sjöström, H. S.; Hilvert, D.; Baker, D.; Zeymer, C. Tight and specific lanthanide binding in a de novo TIM barrel with a large internal cavity designed by symmetric domain fusion. Proc. Natl. Acad. Sci. U.S.A. 2020, 117, 30362-30369.
