Experimental and computational snapshots of C-C bond formation in a C-nucleoside synthase.
Li, W., Girt, G.C., Radadiya, A., Stewart, J.J.P., Richards, N.G.J., Naismith, J.H.(2023) Open Biol 13: 220287-220287
- PubMed: 36629016 
- DOI: https://doi.org/10.1098/rsob.220287
- Primary Citation of Related Structures:  
8AOZ, 8AP0 - PubMed Abstract: 
The biosynthetic enzyme, ForT, catalyses the formation of a C-C bond between 4-amino-1 H -pyrazoledicarboxylic acid and MgPRPP to produce a C-nucleoside precursor of formycin A. The transformation catalysed by ForT is of chemical interest because it is one of only a few examples in which C-C bond formation takes place via an electrophilic substitution of a small, aromatic heterocycle. In addition, ForT is capable of discriminating between the aminopyrazoledicarboxylic acid and an analogue in which the amine is replaced by a hydroxyl group; a remarkable feat given the steric and electronic similarities of the two molecules. Here we report biophysical measurements, structural biology and quantum chemical calculations that provide a detailed molecular picture of ForT-catalysed C-C bond formation and the conformational changes that are coupled to catalysis. Our findings set the scene for employing engineered ForT variants in the biocatalytic production of novel, anti-viral C-nucleoside and C-nucleotide analogues.
Organizational Affiliation: 
Structural Biology, The Rosalind Franklin Institute, Didcot OX11 0QS, UK.