HYDROPHOBIC PATCHES ON THE SURFACES OF PROTEIN STRUCTURES

A survey of hydrophobic patches on the surface of 112 soluble, monomer ic proteins is presented, The largest patch on each individual protein averages around 400 Angstrom(2) but can range from 200 to 1,200 Angst rom(2). These areas are not correlated to the sizes of the proteins an d only weakly to their apolar surface fraction. Ala, Lys, and Pro have dominating contributions to the apolar surface for smaller patches, w hile those of the hydrophobic amino acids become more important as the patch size increases. The hydrophilic amino acids expose an approxima tely constant fraction of their apolar area independent of patch size; the hydrophobic residue types reach similar exposure only in the larg er patches. Though the mobility of residues on the surface is generall y higher, it decreases for hydrophilic residues with increasing patch size. Several characteristics of hydrophobic patches catalogued here s hould prove useful in the design and engineering of proteins. (C) 1996 Wiley-Liss, Inc.