Secondary structure of the HAV peptide which regulates cadherin-cadherin interaction

Cadherins are calcium-binding proteins which are responsible for cell-cell adhesion in biological systems. Cadherins are involved in embryo compaction, neurite growth, cellular differentiation and formation of biological barriers (i.e., intestinal and blood brain barriers). A short linear peptide, LRAHAVDVNG-NH2 (Peptide 1), which contains His-Ala-Val sequence and is derived from the N-cadherin sequence has been shown to inhibit embryo compaction and neurite growth; this is caused by inhibition of the cadherin-cadherin interactions. Peptide 1 was synthesized and its solution conformation was determined by proton nuclear magnetic resonance, circular dichroism and molecular dynamics simulations. These studies indicated that the peptide has an extended structure from residue Leu1 to Asp7, possibly a beta-sheet structure, followed by a beta-turn from Asp7 to Gly10. The X-ray crystal structure of a sequence similar to that of peptide 1 in hemagglutinin indicated that it also has a beta-sheet structure around the HAV sequence, followed by a beta-turn.