A Radical dance in thiamin biosynthesis: Mechanistic analysis of the bacterial hydroxymethylpyrimidine phosphate synthase

Tricky things with ThiC: Hydroxymethylpyrimidine phosphate (HMP-P) synthase (ThiC) catalyzes one of the most complex rearrangement reactions in primary metabolism. Deuteration experiments show that under reducing conditions, in the presence of aminoimidazole ribonucleotide, the 5-deoxyadenosyl radical generated at the active site of ThiC reacts directly with the substrate and performs two iterative hydrogen atom abstraction events to catalyze this rearrangement (see scheme; SAM=S-adenosylmethionine). © 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim