Three-alpha-helical coiled-coil, as a proposed model for a thin rod segment of bacteriophage T3 tail fibers

Three-stranded alpha-helical coiled-coil was considered as a model for a thin proximal rod of T3 phage tail fiber on the basis of amino acid sequence. A segment of residues from ca. 130th to 270th was shown to have a unique feature to satisfy the required conditions of the coiled-coil, and to give the observed geometry.