The failure of the pharmaceutical industry to increase the delivery of new drugs into the market is driving a re-assessment of practices and methods in drug discovery and development. In particular alternative strategies are being pursued to find therapeutics that are more selective, including small molecules that target protein-protein interactions. However, success depends on improving our understanding of the recognition of small molecules by interfaces in order to develop better methods for maximising their affinity and selectivity, whilst trying to confer an appropriate therapeutic profile.

This thesis starts with the description of the creation of TIMBAL, a database that holds small molecules disrupting protein-protein interactions. The thesis then focuses on the analysis of these molecules and their interactions in a medicinal chemistry and structural biology context. TIMBAL molecules are profiled against other sets of molecules (drugs, drug-like and screening compounds) in terms of molecular properties. Using the structural databases in the Blundell group, the atomic detail of the interaction patterns of TIMBAL molecules with their protein targets are compared with other molecules interacting with proteins, comprising natural molecules, small peptides, synthetic small molecules (including drug-like and drugs) and other proteins. The structural features and composition of the binding sites of these complexes are also analysed. Keeping in mind that current drug candidates are somewhat too lipophilic to succeed, these interaction profiles are defined in terms of polar and apolar contacts, with the aim of migrating natural patterns into the design of new therapeutics.