Metal Fluorides as Analogues for Studies on Phosphoryl Transfer Enzymes

The 1994 structure of a transition‐state analogue with AlF 4 − and GDP complexed to G1α, a small G protein, heralded a new field of research into the structure and mechanism of enzymes that manipulate the transfer of phosphoryl (PO 3 − ) groups. The number of enzyme structures in the PDB containing metal fluorides (MF x ) as ligands that imitate either a phosphoryl or a phosphate group was 357 at the end of 2016. They fall into three distinct geometrical classes: 1) Tetrahedral complexes based on BeF 3 − that mimic ground‐state phosphates; 2) octahedral complexes, primarily based on AlF 4 − , which mimic “in‐line” anionic transition states for phosphoryl transfer; and 3) trigonal bipyramidal complexes, represented by MgF 3 − and putative AlF 3 0 moieties, which mimic the geometry of the transition state. The interpretation of these structures provides a deeper mechanistic understanding into the behavior and manipulation of phosphate monoesters in molecular biology. This Review provides a comprehensive overview of these structures, their uses, and their computational development.