Amphiphilic helix is essential for the activity of brain injury-derived neurotrophic peptide (BINP)

To study the structure-activity relationships of brain injury-derived neurotrophic peptide (BINP), 12 analogs were synthesized by replacing each amino acid residue with Gly. BINP showed CD spectra typical of an alpha-helical conformation in TFE solution which mimics the membrane environment. In the alpha-helical conformation, BINP showed an amphiphilic profile. Neurotrophic activities of BINP and its analogs were estimated from the effects on supporting septal cholinergic neurons and on rescuing hippocampal neurons from injury caused by glutamate. Both assays showed that the residues on the hydrophobic side of the amphiphilic helix were essential for the neurotrophic activity.