Regarding the ring opening of epoxide 5 with azide, the inversion in enantioselectivity for formation of regioisomer 6a as well as the improvement in enantioselectivity for generation of regioisomer 6b of the purified variants in comparison to wild-type HheG could be confirmed, while absolute E-values of the selected variants were lower compared to our initial screening results (Table ). The latter is probably the result of the higher conversions (between 30 and 50%) that we aimed for in our reactions using purified enzymes in comparison to the screening. Based on these results, positions 44 to 46 on the loop are likely not the only relevant residues in HheG to steer the enzyme's enantioselectivity in the azidolysis of epoxide 5.