1. Proteus Molecular Design Ltd., Proteus House, Lyme Green Business Park, Macclesfield, Cheshire SK11 0JL, England, Department of Physiology and Pharmacology, University of Southampton, Bassett Crescent East, Southampton SO16 7PX, England, Department of Pure and Applied Chemistry, University of Strathclyde, Glasgow G1 1XL, Scotland, and Department of Pharmaceutical Sciences, Strathclyde Institute for Biomedical Sciences, 27 Taylor Street, Glasgow G4 0NR, Scotland