title: Structural models of the evolutionarily conservative central domain of silk-moth chorion proteins.
abstract: Silk-moth chorion proteins belong to a small number of families: A, B, C, Hc-A and Hc-B. The central domain is an evolutionarily conservative region in each family, of variable length and composition between families. This domain shows clear 6-fold periodicities for various amino acid residues, e.g. glycine. The periodicities, together with the well-documented prevalence of beta-sheet and beta-turn secondary structure of chorion proteins, strongly support a structural model in which four-residue beta-strands alternate with beta-turns, forming a compact antiparallel, probably twisted beta-sheet. Conformational analysis, aided by interactive graphics refinement and recent experimental findings, further suggest that this structure consists of beta-strands, alternating with I' and II' beta-turns, and apparently forms the basis for the molecular and supramolecular assembly of chorion.
authors.affiliation: Department of Biochemistry, Cell and Molecular Biology and Genetics, University of Athens, Greece.
authors.forename: S J
authors.initials: SJ
authors.lastname: Hamodrakas
authors.forename: H E
authors.initials: HE
authors.lastname: Bosshard
authors.forename: C N
authors.initials: CN
authors.lastname: Carlson
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D004527:Egg Proteins; D008565:Membrane Proteins; D008958:Models, Molecular; D008969:Molecular Sequence Data; D011487:Protein Conformation
chemical_list: D004527:Egg Proteins; D008565:Membrane Proteins; C015753:chorion proteins