Membrane‐Associated Nucleobase‐Functionalized β‐Peptides (β‐PNAs) Affecting Membrane Support and Lipid Composition

Protein‐membrane interactions are essential to maintain membrane integrity and control membrane morphology and composition. Cytoskeletal proteins in particular are known to interact to a high degree with lipid bilayers and to line the cytoplasmic side of the plasma membrane with an extensive network structure. In order to gain a better mechanistical understanding of the protein–membrane interplay and possible membrane signaling, we started to develop a model system based on β‐peptide nucleic acids (β‐PNAs). These β‐peptides are known to form stable hydrogen‐bonded aggregates due to their helical secondary structure, which serve to pre‐organize the attached nucleobases. After optimization of the β‐PNA solid‐phase peptide synthesis and validation of helix formation, the ability of the novel β‐PNAs to dimerize and interact with lipid bilayers was investigated by both fluorescence and circular dichroism spectroscopy. It was shown that duplex formation occurs rapidly and with high specificity and could also be detected on the surfaces of the lipid bilayers. Hereby, the potential of a β‐PNA‐based peptide system to mimic membrane‐associated protein networks could be demonstrated.
A model system for membrane‐spanning protein networks – important for the stability of the membrane, its structure and transmembrane signal transmission – has been developed. The synthetically available system is based on β‐peptide nucleic acid (β‐PNA) helices functionalized with lipid membrane anchors and nucleobase recognition sequences. β‐PNA membrane interaction and aggregation are indicated by fluorescence and CD spectroscopy assays.