title: Characterizing α-helical peptide aggregation on supported lipid membranes using microcantilevers.
abstract: We report the use of lipid membrane-coated microcantilevers to probe the interactions between phospholipid membranes and membrane-active peptides. This sensing method integrates two well-developed techniques: solid-supported lipid bilayers (SLBs) and microcantilever sensors. SLBs are prepared on the silicon dioxide surface of the microcantilevers using a vesicle fusion method. As molecules adsorb onto the surface of the microcantilever, the microcantilever bends due to the induced compressive or tensile stresses, which result from the surface free energy change. Real-time surface stress changes in the SLB due to interactions with small molecules can be detected by monitoring the deflection of the microcantilever. We investigate the mechanism for the interaction between SLBs and PEP1, a synthetic amphipathic peptide resembling a segment of the nonstructural protein (NS5A) of the hepatitis C virus. Initially, the PEP1 peptides adsorb onto the lipid membranes, and then at a critical concentration, the peptides begin to aggregate and form pores; finally, the peptides destabilize and induce solubilization of the supported membranes. The membrane-coated microcantilever sensor is capable of characterizing the kinetics and dynamics of this process with great sensitivity.
authors.affiliation: Department of Chemical and Biomolecular Engineering, Rice University , Houston, Texas 77005, United States.
authors.forename: Jinghui
authors.initials: J
authors.lastname: Wang
authors.forename: Kai-Wei
authors.initials: KW
authors.lastname: Liu
authors.forename: Sibani Lisa
authors.initials: SL
authors.lastname: Biswal
mesh_terms: D008567:Membranes, Artificial; D010455:Peptides / Q000737:chemistry*; D010743:Phospholipids / Q000737:chemistry*; D013499:Surface Properties; D017361:Viral Nonstructural Proteins / Q000737:chemistry; D012324:RNA-Dependent RNA Polymerase
chemical_list: D008567:Membranes, Artificial; D010455:Peptides; D010743:Phospholipids; D017361:Viral Nonstructural Proteins; C087036:NS-5 protein, hepatitis C virus; D012324:RNA-Dependent RNA Polymerase