Cover Picture (Angew. Chem. Int. Ed. Engl. 6/1993)

The cover picture shows schematically the β‐spiral structure of poly(GVGVP) (left) and the polypeptides designed from it, containing Glu residues (red) and hydrophobic Phe residues (white and pink). The optimal arrangement of the Phe residues about the Glu residues for the spiral structure in the polypeptide on the right, which contains three pentamers per turn of the β‐spiral, gives the Glu residues of this polypeptide in water a p K a of 8.1, whereas the same residue that is, however, incorporated randomly into 20 % of the pentamers in the second peptide from the left has a p K a of 4.3. This example of the effect of the interplay between polar and apolar groups on hydration shows the extent to which such characteristics can influence the physical and chemical properties of polymeric structures, including protein folding. Such effects contribute to a better understanding of phenomena such as muscle contraction in living organisms. More on this fascinating research field is related in D. W. Urry's review on p. 819 ff.