Roelfes, G.

ACS Cent. Sci. 2019, 5, 206-208, 10.1021/acscentsci.9b00015

Directed evolution generated an enzyme for the enantioselective synthesis of α-trifluoromethylated organoborons—potentially attractive synthons for fluorinated compounds.

Hayashi, T

Chem. Commun. 2011, 47, 8229, 10.1039/c1cc11157d

The diiron carbonyl cluster is held by a native CXXC motif, which includes Cys14 and Cys17, in the cytochrome c sequence. It is found that the diiron carbonyl complex works well as a catalyst for H2 evolution. It has a TON of ∼80 over 2 h at pH 4.7 in the presence of a Ru-photosensitizer and ascorbate as a sacrificial reagent in aqueous media.

Imperiali, B.

Prot. Eng. 1997, 10, 691-698, 10.1093/protein/10.6.691

The transaminase activity of two new semisynthetic RNase-S proteins incorporating a pyridoxamine moiety at the active site has been evaluated. A chemically competent derivative of pyridoxamine phosphate was incorporated into the C-peptide fragments of these non-covalent protein complexes in the form of an unnatural coenzyme-amino acid chimera, 'Pam'. The chimeric Pam residue integrates the heterocyclic functionality of pyridoxamine phosphate into the side chain of an alpha-amino acid and was introduced instead of Phe8 into the C-peptide sequence via standard solid phase methodology. The two semisynthetic Pam-RNase constructs were designed to probe whether the native ribonuclease catalytic machinery could be enlisted to modulate a pyridoxamine-dependent transamination reaction. Both RNase complexes, H1SP and S1SP, exhibited modest rate enhancements in the Cu(II)-assisted transamination of pyruvate to alanine under single turnover conditions, relative to 5'-deoxypyridoxamine and the uncomplexed C-peptide fragments. Furthermore, multiple turnovers of substrates were achieved in the presence of added L-phenylalanine due to recycling of the pyridoxamine moiety. The modest chiral inductions observed in the catalytic production of alanine and the differences in reactivity between the two proteins could be rationalized by the participation of a general base (His12) in complex H1SP, and by the increased tolerance for large amino acid substrates by complex S1SP, which contains serine at this position. The pyridoxamine-amino acid chimera will be useful in the future for examining the coenzyme structure/ function relationships in a native-like peptidyl architecture.