title: Three-stranded alpha-fibrous proteins: the heptad repeat and its implications for structure.
abstract: Amino acid sequence data have been collected for the coiled-coil rod domains of three-stranded alpha-fibrous proteins--fibrinogen, laminin, tenascin, macrophage scavenger receptor protein and the leg fibre protein from bacteriophage. Such domains are characterized by a heptad substructure in which apolar residues occur alternately three and four residues apart. The distribution of residues in each position of the heptad has been analysed, and the results compared with those obtained for the two-stranded alpha-fibrous proteins, which include the intermediate filament and myosin families. Distinctions can be drawn between the sequences in two- and three-stranded coiled-coil structures and these provide criteria that will prove useful in predicting secondary and tertiary structure purely from sequence data.
authors.affiliation: Department of Physics and Biophysics, Massey University, Palmerston North, New Zealand.
authors.forename: J F
authors.initials: JF
authors.lastname: Conway
authors.forename: D A
authors.initials: DA
authors.lastname: Parry
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D015816:Cell Adhesion Molecules, Neuronal / Q000737:chemistry*; D016326:Extracellular Matrix Proteins / Q000737:chemistry*; D005340:Fibrinogen / Q000737:chemistry*; D006801:Humans; D007797:Laminin / Q000737:chemistry*; D046911:Macromolecular Substances; D008264:Macrophages; D008565:Membrane Proteins; D008969:Molecular Sequence Data; D015394:Molecular Structure; D009842:Oligopeptides / Q000737:chemistry; D010455:Peptides / Q000737:chemistry; D011487:Protein Conformation; D011971:Receptors, Immunologic / Q000737:chemistry*; D018110:Receptors, Lipoprotein; D051116:Receptors, Scavenger; D051122:Scavenger Receptors, Class B; D013604:T-Phages; D019063:Tenascin; D014764:Viral Proteins / Q000737:chemistry*
chemical_list: D015816:Cell Adhesion Molecules, Neuronal; D016326:Extracellular Matrix Proteins; D007797:Laminin; D046911:Macromolecular Substances; D008565:Membrane Proteins; D009842:Oligopeptides; D010455:Peptides; D011971:Receptors, Immunologic; D018110:Receptors, Lipoprotein; D051116:Receptors, Scavenger; C454739:Scarb1 protein, mouse; D051122:Scavenger Receptors, Class B; D019063:Tenascin; D014764:Viral Proteins; C069680:bacteriophage T7 leg protein gp17; D005340:Fibrinogen