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 sho rt linear peptide, LRAHAVDVNG-NH2 (Peptide 1), which contains His-Ala- Val sequence and is derived from the N-cadherin sequence has been show n to inhibit embryo compaction and neurite growth; this is caused by i nhibition of the cadherin-cadherin interactions. Peptide 1 was synthes ized and its solution conformation was determined by proton nuclear ma gnetic resonance, circular dichroism and molecular dynamics simulation s. These studies indicated that the peptide has an extended structure from residue Leu1 to Asp7, possibly a beta-sheet structure, followed b y a beta-turn from Asp7 to Gly10. The X-ray crystal structure of a seq uence 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.