Selective protein degradation by ligand-targeted enzymes: Towards the creation of catalytic antagonists

Molecular angler fish: By precisely positioning different binding ligands (L) around the active site "mouth" of a degradative proteinase enzyme, target proteins (TP) can be plucked from solution, locked in position adjacent to the catalytic triad "jaws", and in this way readily and specifically degraded (see scheme). In this strategy, the appropriate ligand acts as a homing device to confer and enhance selectivity, in the best case by more than 350-fold, in a generic process that exploits the intrinsic, ligand-recognition capabilities of the protein target to trigger its own destruction. The hunting strategy of the deep sea Angler Fish, which uses a lure above its mouth, illustrates this principle.