Structure of coiled beta-beta-hairpins and beta-beta-corners.

Two types of super-secondary structure, coiled beta-beta-hairpins and beta-beta-corners, are considered in this paper. A beta-beta-corner can be represented as a long beta-beta-hairpin folded orthogonally on itself so that the strands, when passing from one layer to the other, rotate in a right-handed direction about an imaginary axis. It is shown that a beta-beta-hairpin, forming a coiled coil structure or a beta-beta-corner, is right-handed when viewed from the concave side. These unique arrangements of beta-strands in the coiled beta-beta-hairpins and beta-beta-corners are of particular value in protein modelling and prediction.