| advertisement: compare things at compare-stuff.com! |
As in the folding of protein structures, hydrophobicity is also one of the major forces in ligand recognition. As the hydrophobic side-chains of a folding chain, or two interacting molecules come together there is a favourable increase in the entropy of the system as the solvent (water) molecules which were previously in an ordered shell around the exposed hydrophobic surface become disordered. There is also an energetic contribution as unfavourable apolar-polar interactions are replaced with more favourable homotypic interactions. Thus the recognition surfaces of proteins and ligands are often more hydrophobic than `normal' protein surfaces (Chothia & Janin, 1975; S. Jones & Thornton, 1996).