A Promiscuous De Novo Retro‐Aldolase Catalyzes Asymmetric Michael Additions via Schiff Base Intermediates

Abstract

Recent advances in computational design have enabled the development of primitive enzymes for a range of mechanistically distinct reactions. Here we show that the rudimentary active sites of these catalysts can give rise to useful chemical promiscuity. Specifically, RA95.5-8, designed and evolved as a retro-aldolase, also promotes asymmetric Michael additions of carbanions to unsaturated ketones with high rates and selectivities. The reactions proceed by amine catalysis, as indicated by mutagenesis and X-ray data. The inherent flexibility and tunability of this catalyst should make it a versatile platform for further optimization and/or mechanistic diversification by directed evolution.

Chemoselective Henry Condensations Catalyzed by Artificial Carboligases

“…This catalyst uses a nucleophilic lysine to promote the retro‐aldol reaction for which it was designed (Scheme A) . It can also exploit Schiff‐base adducts to accelerate several other transformations, including the addition of ethyl 2‐cyanoacetone to iminium‐activated enones and aldehydes to afford Michael and Knoevenagel products, respectively (Scheme B, C). RA95.5‐8 also catalyzes Michael‐type additions of nitromethane to iminium‐activated enones, as well as enamine‐mediated additions of acetone to electrophilic nitroolefins .…”

“…A) Retro‐aldol cleavage of methodol . B) Michael addition of conjugated ketones and carbon nucleophiles (Nu=ethyl 2‐cyanoacetate, nitromethane) . C) Knoevenagel condensation of electron‐rich aldehydes (R=H, Me) and ethyl 2‐cyanoacetate .…”

GDCh Innovation Prize in Medicinal/Pharmaceutical Chemistry: D. Schade and A. Koeberle / Feodor Lynen Lectureship: D. Hilvert / Roy L. Whistler Award: B. G. Davis

“…Hilvert and his group are interested in developing general strategies for engineering proteins with novel structures and activities, particularly catalysis. He has reported in Angewandte Chemie on enzyme catalysis, and the encapsulation of enzymes in protein cages . Hilvert is Co‐Chair of the Editorial Advisory Board of ChemBioChem , and is also on the Editorial Board of Molecular Informatics .…”

Innovationspreis in Medizinischer/Pharmazeutischer Chemie der GDCh: D. Schade und A. Koeberle / Feodor‐Lynen‐Vorlesung: D. Hilvert / Roy L. Whistler Award: B. G. Davis

“…Hilvert sucht nach allgemeinen Strategien für das Engineering von Proteinen mit neuartigen Strukturen und Aktivitäten, vor allem in der Katalyse. Er hat in der Angewandten Chemie über die Katalyse durch Enzyme und das Einschließen von Enzymen in Proteinkäfige berichtet . Hilvert ist einer der Vorsitzenden des Editorial Advisory Board von ChemBioChem , und er gehört dem Editorial Board von Molecular Informatics an.…”