Front Cover: Re‐Programming and Optimization of a L‐Proline cis‐4‐Hydroxylase for the cis‐3‐Halogenation of its Native Substrate (ChemCatChem 18/2021)

The Front Cover represents the discovery of a novel path during a scientist′s journey towards the biocatalytic incorporation of chlorine into L‐proline. In their Communication, A. Papadopoulou et al describe the remodeling of an Fe/αKG hydroxylase into a halogenase utilizing the tools of protein engineering. By employing several rounds of directed evolution, a remodeled halogenase variant with a 98‐fold improved apparent kcat/Km was generated. The reprogrammed biocatalyst is the first example of a stereo‐ and regioselective halogenase derivatizing L‐proline at the C3 position and highlights the possibility to successfully access the diverse chemistries of Fe/αKG‐dependent dioxygenases to expand the biocatalytic toolbox. More information can be found in the Communication by A. Papadopoulou et al.