Structure-Guided Reprogramming of a Hydroxylase to Halogenate Its Small Molecule Substrate

Enzymatic installation of chlorine/bromine into unactivated carbon centers provides a versatile, selective, and environmentally friendly alternative to chemical halogenation. Iron(II) and 2-(oxo)-glutarate (Fe^II/2OG)-dependent halogenases are powerful biocatalysts that are capable of cleaving aliphatic C-H bonds to introduce useful functional groups, including halogens. Using the structure of the Fe/2OG halogenase, WelO5, in complex with its small molecule substrate, we identified a similar N-acyl amino acid hydroxylase, SadA, and reprogrammed it to halogenate its substrate, thereby generating a new chiral haloalkyl center. The work highlights the potential of Fe^II/2OG enzymes as platforms for development of novel stereospecific catalysts for late-stage C-H functionalization.