Keinan, E.

J. Am. Chem. Soc. 1999, 121, 8978-8982, 10.1021/ja990314q

An antibody−metalloporphyrin assembly that catalyzes the enantioselective oxidation of aromatic sulfides to sulfoxides is presented. Antibody SN37.4 was elicited against a water-soluble tin(IV) porphyrin containing an axial α-naphthoxy ligand. The catalytic assembly comprising antibody SN37.4 and a ruthenium(II) porphyrin cofactor exhibited typical enzyme characteristics, such as predetermined oxidant and substrate selectivity, enantioselective delivery of oxygen to the substrate, and Michaelis−Menten saturation kinetics. This assembly, which promotes a complex, multistep catalytic event, represents a close model of natural heme-dependent oxidation enzymes.

Kim, H.S.

Science 2006, 311, 535-538, 10.1126/science.1118953

The design of enzymes with new functions and properties has long been a goal in protein engineering. Here, we report a strategy to change the catalytic activity of an existing protein scaffold. This was achieved by simultaneous incorporation and adjustment of functional elements through insertion, deletion, and substitution of several active site loops, followed by point mutations to fine-tune the activity. Using this approach, we were able to introduce β-lactamase activity into the αβ/βα metallohydrolase scaffold of glyoxalase II. The resulting enzyme, evMBL8 (evolved metallo β-lactamase 8), completely lost its original activity and, instead, catalyzed the hydrolysis of cefotaxime with a (kcat /Km)app of 1.8 × 102 (mole/liter)–1 second–1, thus increasing resistance to Escherichia coli growth on cefotaxime by a factor of about 100.

Clever, G.H.

J. Am. Chem. Soc. 2021, 143, 3555-3561, 10.1021/jacs.0c13251

Metal-binding DNA structures with catalytic function are receiving increasing interest. Although a number of metalloDNAzymes have been reported to be highly efficient, the exact coordination/position of their catalytic metal center is often unknown. Here, we present a new approach to rationally develop metalloDNAzymes for Lewis acid-catalyzed reactions such as enantioselective Michael additions. Our strategy relies on the predictable folding patterns of unimolecular DNA G-quadruplexes, combined with the concept of metal-mediated base-pairing. Transition-metal coordination environments were created in G-quadruplex loop regions, accessible by substrates. Therefore, protein-inspired imidazole ligandoside L was covalently incorporated into a series of G-rich DNA strands by solid-phase synthesis. Iterative rounds of DNA sequence design and catalytic assays allowed us to select tailored metalloDNAzymes giving high conversions and excellent enantioselectivities (≥99%). Based on their primary sequence, folding pattern, and metal coordination mode, valuable information on structure–activity relationships could be extracted. Variation of the number and position of ligand L within the sequence allowed us to control the formation of (S) and (R) enantiomeric reaction products, respectively.