title: Sequence diagrams and the presentation of structural and evolutionary relationships among proteins.
abstract: Protein sequences mapped on two-dimensional diagrams show characteristic patterns that should be of value in visualising sequence information and in distinguishing simpler structures. A convenient map form for comparative purposes is the alpha-helix diagram with aminoacid distribution analogous to the surface of an alpha-helix oriented so that an alpha-helix structure corresponds on the diagram to a vertical band 3.6 residues wide. The sequence diagram for an alpha-keratin, high-sulphur protein suggests a new form of polypeptide helix based on a repeating unit of five which may be an important component of alpha-keratin fibres.
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D005075:Biological Evolution; D003013:Clostridium; D003094:Collagen; D004926:Escherichia coli / Q000648:ultrastructure; D005288:Ferredoxins; D006657:Histones; D007633:Keratins; D008074:Lipoproteins; D008566:Membranes; D009211:Myoglobin; D011487:Protein Conformation; D014907:Whales
chemical_list: D005288:Ferredoxins; D006657:Histones; D008074:Lipoproteins; D009211:Myoglobin; D007633:Keratins; D003094:Collagen