Lock-and-key paradigm

A high steric complementarity between the protein and the ligand. This observation is consistent with the long established lock-and-key paradigm. 

Supramolecular Chemistry - From the Lock-and-Key Image to the Information Paradigm, 1, 307. 

Lehn J-M (1994) Perspectives in supramolecular chemistry from the lock-and-key image to the information paradigm. In Behr JP (ed) Perspectives in supramolecular chemistry, vol 1. The lock-and-key principle. The state of the art - 100 years on. Wiley, Chichester, p 307... 

Similarity has played an important role in the discussion of structure-property relationships, particularly in discussions of biological activity of chemicals. The early recognition of the role of molecular similarity in structure-activity studies may be traced to Email Fischer s lock and key model for the interaction of proteins and drugs. Much of the works in QSAR studies rests on the paradigm that similar structures have similar properties. In recent years, attempts have been made to express the degree of mutual similarity quantitatively. One of the ways to describe similarity is to express it by a series of 2-dimensional and 3-dimensional molecular descriptors as follows ... 

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