The Silkmoth Eggshell as a Natural Amyloid Shield for the Safe Development of Insect Oocyte and Embryo: Insights From Studies of Silkmoth Chorion Protein Peptide-Analogues of the B Family

Silkmoth chorion is the major component of the silkmoth eggshell. The proteins that constitute more than 95% of its dry mass have remarkable mechanical and physicochemical properties forming a protective natural shield for the oocyte and the developing embryo from a wide range of environmental hazards. Peptide-analogues of the central conservative domain of the two major families of silk moth chorion proteins, the A's and the B's, form amyloid fibrils under a variety of conditions, which prompted us to propose, 10 years ago, that silkmoth chorion is an amyloid with protective properties. Following our finding, a number of studies verified the existence of several functional amyloids. In this study, we designed, synthesized and studied two peptide-analogues of the central conservative domain of the B family of silkmoth chorion proteins, and we present experimental results, which show: (a) that the amyloidogenic properties of silkmoth chorion peptides are encoded into the tandemly repeating hexapeptides comprising the central domain of silkmoth chorion proteins, confirming our previous findings from peptide analogues of the A family of chorion proteins, and, (b) they suggest how silkmoth chorion proteins of the B family self-assemble in vivo, for the formation of the helicoidal architecture of silkmoth chorion. (C) 2011 Wiley Periodicals, Inc. Biopolymers (Pept Sci) 96: 723-733, 2011.