Targeting Tyrosine-Anchored Nonapeptides for Lipid-Binding Events

Short polypeptides are increasingly used in cancer research as modular systems for selectively targeting cellular environments, including membrane interfaces that regulate signaling and trafficking. These applications rely on the ability of short sequences to encode specific interactions with defined biological targets. One such target class is angiomotins (Amots), adaptor proteins that regulate cell proliferation and differentiation through selective binding to phosphatidylinositol-containing membranes, followed by membrane deformation and lipid reorganization. Because this activity depends on sequence-specific membrane recognition, angiomotin provides a useful model for determining how local peptide structure drives selective membrane interaction. However, the structural basis for this interaction and the role of individual tyrosine residues within the Amot80/130 coiled-coil homology domain remain unclear. To address this, nine-amino-acid peptides (nonapeptides) centered on the five native tyrosines were studied to determine how local sequence context influences membrane interaction. Nuclear magnetic resonance spectroscopy in solution indicates that these peptides adopt defined structural features, including restricted tyrosine ring motion and inter-residue contacts. Absorbance and fluorescence measurements in hydrophobic solvent systems and lipid-containing vesicle preparations show sequence-dependent differences consistent with variations in hydrophobic partitioning and lipid headgroup interactions. Computational modeling using solution NMR structural models further identifies sequence- and conformation-dependent differences in lipid-headgroup contacts, membrane orientation, and predicted membrane insertion. Together, these results support a model that local sequence context surrounding individual tyrosines governs selective interaction with hydrophobic environments and phosphatidylinositol-containing membranes, providing a framework for peptide-based membrane targeting in cancer-relevant systems.