A small molecule that locks an essential enzyme in an inactive form could one day form the basis of a new class of unbeatable, species-specific drugs, including antibiotics.

PBGS, an enzyme used by nearly all cellular life, is a morpheein -- a molecule that spontaneously "shape-shifts," -- turning from an active octamer (eight part) protein to a hexamer (six part).

Morphlock stabilizes the hexamer, thereby turning off the enzyme.