The probability that a residue in a protein is part of a coiled-coil structure was assessed by comparison of its flanking sequences with sequences of known coiled-coil proteins. This method was used to delineate coiled-coil domains in otherwise globular proteins, such as the leucine zipper domains in transcriptional regulators, and to predict regions of discontinuity within coiled-coil structures, such as the hinge region in myosin. More than 200 proteins that probably have coiled-coil domains were identified in GenBank, including alpha- and beta-tubulins, flagellins, G protein beta subunits, some bacterial transfer RNA synthetases, and members of the heat shock protein (Hsp70) family.