De novo design, synthesis and characterization of membrane-active peptides

Our current level of understanding of membrane-protein folding is primitive, but it is beginning to advance. Previously [Choma, Gratkowski, Lear and DeGrado (2000) Nat. Struct. Biol. 7, 161–166], we described studies of the association in detergent micelles of short, simple-sequence hydrophobic peptides modified from the sequence of the water-soluble, homodimeric coiled-coil GCN4-P1 peptide using the principle that the interiors of membrane proteins are similar to those of water-soluble proteins. Here, we discuss more quantitative aspects of the association equilibrium and compare the free energies of association of a number of mutant peptides designed to explore specific features responsible for the association.