Summary:
All mammalian oocytes are enclosed by a proteinaceous coat, called zona
pellucida (ZP) that protects the egg until it is fully developed and implanted
in the uterus and is also bound to play a crucial role during fertilization.
This extracellular porous matrix is a filamentous structure, composed of 3
glycoproteins (ZP1-3), that share a conserved seqeunce at their C-terminal end,
designated as the ZP domain. It is divided into two domains: the N-terminal
region named ZP-N and the C-terminal region known as the ZP-C domain. The ZP-N
domain is responsible for protein polymerization, whereas the ZP-C probably
contributes to protein function. Analysis of the structure of ZP-N domain and
detailed study of the results produced by the “AMYLPRED” algorithm application,
an amyloidogenic determinant prediction algorithm developed in our lab, led us
to synthesize peptide-analogues of parts of the human ZP-1 protein, predicted
as potential amyloidogenic determinants. Experimental data clearly indicate
that these peptides actually fold and self-assemble into amyloid-like fibrils.
A possible model is proposed suggesting how ZP protein polymerization might
occur for the formation of zona pellucida. This data most probably indicate
that zona pellucida is a natural protective amyloid.
Keywords:
Natural amyloids, Zona pellucida, Peptide-analogues, Modeling, AMYLPRED
