Figure 2.

Comparison of helix packing between membrane and soluble proteins. The soluble proteins were classified according to Michie et al. (26). (A) Contributions to helix packing by different amino acid classes. The packing values in Table 3 were combined for small (A,G), hydroxyl (S,T), amide (N,Q), charged (D,E,R,H,K), hydrophobic (I,L,M,V), and aromatic (F,W,Y) amino acids. The contribution of each amino acid class is plotted by taking the difference between the average packing value for the amino acid class and the average packing value for the protein class as described in the text. These data reflect only the helical portions of the proteins studied. (B) Contribution of amino acid classes to the overall packing in different classes of helical proteins. The packing value differences plotted in A are multiplied by the percent occurrence of the amino acid class for each protein class.