FIGURE 8.

Contact map of protein L (bottom left) and ubiquitin (top right). Side-chain contacts (nearest distance between atoms of two residues <5 Å, calculated by CSU software (68)) made by pairs of amino acids within structural unit 1 (β-hairpin 1 and the helix) or within structural unit 2 (β-hairpin 2) are shown by green and red squares, respectively. Contacts made between these structural units are shown in black. β-strands (labeled I to IV as in Fig. 1) and α-helices, predicted by DSSP (67), are shown as arrows and rectangles, respectively, alongside each contact map. The two structural units are colored green (unit 1) and red (unit 2) in each protein and are also shown superimposed onto the three-dimensional structure of protein L (left) and ubiquitin (right).