title: Amyloid fibril formation propensity is inherent into the hexapeptide tandemly repeating sequence of the central domain of silkmoth chorion proteins of the A-family.
abstract: Peptide-analogues of the A and B families of silkmoth chorion proteins form amyloid fibrils under a variety of conditions [Iconomidou, V.A., Vriend, G. Hamodrakas, S.J. 2000. Amyloids protect the silkmoth oocyte and embryo. FEBS Lett. 479, 141-145; Iconomidou,V.A., Chryssikos, G.D.,Gionis, V., Vriend, G., Hoenger, A., Hamodrakas, S.J., 2001. Amyloid-like fibrils from an 18-residue peptide-analogue of a part of the central domain of the B-family of silkmoth chorion protein. FEBS Lett. 499, 268-273; Hamodrakas, S.J. Hoenger, A., Iconomidou, V. A., 2004 . Amyloid fibrillogenesis of silkmoth chorion protein peptide-analogues via a liquid crystalline intermediate phase. J. Struct. Biol. 145, 226-235.], which led us to propose that silkmoth chorion is a natural protective amyloid. In this study, we designed and synthesized two mutant peptide-analogues of the central conservative domain of the A family: (a) one, cA_m1, with a length half of that of the central domain of the A family, which folds and self-assembles, in various conditions, into amyloid fibrils very similar in properties and structure to the fibrils formed by the cA peptide, which corresponds to the entire length of the A family central domain [Iconomidou, V.A., Vriend, G. Hamodrakas, S.J. 2000. Amyloids protect the silkmoth oocyte and embryo. FEBS Lett. 479, 141-145.], in full support of our previous proposal, (b) the second, cA_m2, differing from cA_m1 at three positions, where three glutamates have replaced two valines and one alanine residues, does not form amyloid fibrils in any conditions. It appears that (a) the amyloidogenic properties of silkmoth chorion peptides are encoded into the tandemly repeating hexapeptides comprising the central domain of silkmoth chorion proteins, and, that (b) suitable mutations, properly and carefully designed, greatly affect the strong amyloidogenic properties inherent in certain aminoacid sequences and may inhibit amyloid formation.
authors.affiliation: Department of Cell Biology and Biophysics, Faculty of Biology, University of Athens, Panepistimiopolis, Athens 157 01, Greece.
authors.forename: Vassiliki A
authors.initials: VA
authors.lastname: Iconomidou
authors.forename: Georgios D
authors.initials: GD
authors.lastname: Chryssikos
authors.forename: Vassilis
authors.initials: V
authors.lastname: Gionis
authors.forename: Athanassios S
authors.initials: AS
authors.lastname: Galanis
authors.forename: Paul
authors.initials: P
authors.lastname: Cordopatis
authors.forename: Andreas
authors.initials: A
authors.lastname: Hoenger
authors.forename: Stavros J
authors.initials: SJ
authors.lastname: Hamodrakas
mesh_terms: D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D000682:Amyloid / Q000737:chemistry* / Q000378:metabolism; D000818:Animals; D012831:Bombyx / Q000235:genetics / Q000378:metabolism*; D003198:Computer Simulation; D004527:Egg Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D019476:Insect Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D008958:Models, Molecular; D008969:Molecular Sequence Data; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D017386:Sequence Homology, Amino Acid; D013055:Spectrophotometry, Infrared; D014961:X-Ray Diffraction
chemical_list: D000682:Amyloid; D004527:Egg Proteins; D019476:Insect Proteins; C015753:chorion proteins