Uncovering the chemistry of C-C bond formation in C-nucleoside biosynthesis: crystal structure of a C-glycoside synthase/PRPP complex.

The enzyme ForT catalyzes C-C bond formation between 5 '-phosphoribosyl-1 '-pyrophosphate (PRPP) and 4-amino-1H-pyrazole-3,5-dicarboxylate to make a key intermediate in the biosynthesis of formycin A 5 '-phosphate byStreptomyces kaniharaensis. We report the 2.5 angstrom resolution structure of the ForT/PRPP complex and locate active site residues critical for PRPP recognition and catalysis.