Structural studies of “aggregation‐prone” peptide‐analogues of teleostean egg chorion ZPB proteins

Egg envelopes of vertebrates are composed of a family of proteins called zona pellucida (ZP) proteins, which are distinguished by the presence of a common structural polymerizing motif, known as ZP domain. Teleostean fish chorion is a fibrous structure, consisting of protein members of the ZPB/ZP1 and the ZPC/ZP3 families, which are incorporated as tandemly repeating heterodimers inside chorion fibers. Computational analysis of multiple ZPB/ZP1 proteins from several teleostean species, reveals two potential “aggregation‐prone” sequence segments, forming a specific polymerization interface (AG interface). These two peptides were synthesized and results are presented in this work from transmission electron microscopy, Congo red staining, X‐ray fiber diffraction and ATR FT‐IR, which clearly display the ability of these peptides to self‐aggregate, forming amyloid‐like fibrils. This, most probably implies that the AG interface of ZPB/ZP1 proteins plays an important role for the formation of the repeating ZPB‐ZPC heterodimers, which constitute teleostean chorion fibrils. © 2014 Wiley Periodicals, Inc. Biopolymers (Pept Sci) 102: 427–436, 2014.