Complementary packing of alpha-helices in proteins

The packing of alpha-helices in proteins is restricted by both the principl e of close packing and the chemical nature of side chains. As a result, (1) a-helical surfaces forming the interface should be complementary to each o ther, (2) hydrophobic stripes of the alpha-helices should fit together like pieces of a jigsaw puzzle, and (3) buried polar side chains (if there are any) should be arranged in a complementary fashion, (C) 1999 Federation of European Biochemical Societies.