Structure-guided ZDHHC engineering exemplified for ZDHHC7 (see also Extended Data Figs. 9 and 10). ZDHHC7 homology model (yellow/orange) overlayed on experimental ZDHHC20 structure (dark green) identifies a potential hole-generating amino acid (Leu57) on an adjacent helix in the vicinity of ZDHHC20 Tyr181; lipid density (blue mesh), and length/size probe analysis identifies a mutant/probe pair (ZDHHC7(L57G)/20-Bz) with optimal activity and selectivity over WT ZDHHC7.