Review: conformation and folding of novel beta-structural elements in viral fiber proteins: the triple beta-spiral and triple beta-helix

Apart from alpha-helical coiled coils and the collagen triple helices, fibrous proteins can contain beta-structure in various conformations. Elongated enzymes such as pectate lyase and the bacteriophage P22 tailspike protein contain single-stranded beta-helices. Virus and bacteriophage fibers, which are often trimeric, have been shown to contain novel triple-stranded beta-structures such as the triple beta-spiral and the triple beta-helix. The conformation and folding of viral fibers containing beta-structure are discussed.