Are the fusion processes involved in birth, life and death of the cell depending on tilted insertion of peptides into membranes?

Various peptide segments have been modeled as asymmetric amphipathic alpha- helices. Theoretical calculations have shown that they insert obliquely int o model membranes. They have been named "tilted peptides". Molecular modeli ng results reported here also evidence the presence of tilted peptides in A DM-1 protein of Caenorhabditis elegans that may be involved in fusion event s, in meltrin alpha, a protein implicated in myoblast fusion, in hemaggluti nin of influenza virus, in the E2 glycoprotein of rubella virus, in the S p rotein of hepatitis B virus, in a subdomain of Ebola virus and in the malar ia CS protein. Experimental results have indicated that tilted peptide frag ments may be involved in cellular life events like sperm-egg fecondation, m uscle development, protein translocation through signal sequences and cellu lar death caused by viral infection or parasite infestation. We speculate t hat membrane destabilization by these tilted peptides may be an important c ommon step in life processes involving fusion phenomena. (C) 1999 Academic Press.