Learte Aymamí, SorayaMartínez Castro, LauraGonzález González, CarmenCondeminas Rodríguez, MiriamMartín Malpartida, PauTomás Gamasa, MaríaBaúlde Álvarez, SandraCouceiro, José R.Maréchal, Jean-DidierMacias, Maria J.Mascareñas Cid, José LuisVázquez Sentís, Marco Eugenio2024-09-252024-09-252024-06-23JACS Au 2024, 4, 7, 2630–26392691-3704http://hdl.handle.net/10347/34877The development of transition metal-based catalytic platforms that promote bioorthogonal reactions inside living cells remains a major challenge in chemical biology. This is particularly true for palladium-based catalysts, which are very powerful in organic synthesis but perform poorly in the cellular environment, mainly due to their rapid deactivation. We now demonstrate that grafting Pd(II) complexes into engineered β-sheets of a model WW domain results in cell-compatible palladominiproteins that effectively catalyze depropargylation reactions inside HeLa cells. The concave shape of the WW domain β-sheet proved particularly suitable for accommodating the metal center and protecting it from rapid deactivation in the cellular environment. A thorough NMR and computational study confirmed the formation of the metal-stapled peptides and allowed us to propose a three-dimensional structure for this novel metalloprotein motifengAtribución 4.0 Internacional© 2024 The Authors. Published by American Chemical Society. This publication is licensed under CC-BY 4.0http://creativecommons.org/licenses/by/4.0/Intracellular catalysisPeptide engineeringMetallopeptidesGraftingPalladiumOrganometallic catalysisjournal article10.1021/jacsau.4c003792691-3704open access