title: The spectrin family of proteins: a unique coiled-coil fold for various molecular surface properties.
abstract: The spectrin superfamily is composed of proteins involved in cytolinker functions. Their main structural feature is a large central subdomain with numerous repeats folded in triple helical coiled-coils. Their similarity of sequence was considered to be low without detailed quantification of the intra- and intermolecular levels. Among the superfamily, we considered as essential to propose an overview of the surface properties of all the repeats of the five proteins of the spectrin family, namely α- and β-spectrins, α-actinin, dystrophin and utrophin. Therefore, the aim of this work was to obtain a quantitative comparison of all the repeats at both the primary sequence and the three-dimensional levels. For that purpose, we applied homology modelling methods to obtain structural models for successive and overlapping tandem repeats of the human erythrocyte α- and β-spectrins and utrophin, as previously undertaken for dystrophin, and we used the known structure of α-actinin. The matrix calculation of the pairwise similarities of all the repeat sequences and the electrostatic and hydrophobic surface properties throughout the protein family support the view that spectrins and α-actinin on one hand and utrophin and dystrophin on the other hand share some structural similarities, but a detailed molecular characterisation highlights substantial differences. The repeats within the family are far from identical, which is consistent with their multiple interactions with different cellular partners, including proteins and membrane lipids.
authors.affiliation: Université de Rennes 1, 35000 Rennes, France; CNRS UMR6290, Institut de Génétique et Développement de Rennes, CS 34317, 35043 Rennes, France.
authors.forename: Aurélie
authors.initials: A
authors.lastname: Nicolas
authors.affiliation: Université de Rennes 1, 35000 Rennes, France; CNRS UMR6290, Institut de Génétique et Développement de Rennes, CS 34317, 35043 Rennes, France.
authors.forename: Olivier
authors.initials: O
authors.lastname: Delalande
authors.affiliation: Université de Rennes 1, 35000 Rennes, France; CNRS UMR6290, Institut de Génétique et Développement de Rennes, CS 34317, 35043 Rennes, France.
authors.forename: Jean-François
authors.initials: JF
authors.lastname: Hubert
authors.affiliation: Université de Rennes 1, 35000 Rennes, France; CNRS UMR6290, Institut de Génétique et Développement de Rennes, CS 34317, 35043 Rennes, France. Electronic address: elisabeth.lerumeur@univ-rennes1.fr.
authors.forename: Elisabeth
authors.initials: E
authors.lastname: Le Rumeur
mesh_terms: D000595:Amino Acid Sequence; D005091:Exons; D057927:Hydrophobic and Hydrophilic Interactions; D007526:Isoelectric Point; D008969:Molecular Sequence Data; D011487:Protein Conformation; D020449:Repetitive Sequences, Amino Acid; D013049:Spectrin / Q000737:chemistry*; D055672:Static Electricity; D040681:Structural Homology, Protein; D049411:Utrophin / Q000737:chemistry
chemical_list: D049411:Utrophin; D013049:Spectrin
keywords: Coiled-coil; Homology modelling; Sequence similarity; Spectrin-like repeats