Abstract
Quasielastic neutron scattering (QENS) is well suited for studying the dynamics of water in proximity to supported membranes whose structure can be characterized by atomic force microscopy (AFM). Here we use QENS to investigate the effect of an adsorbed peptide (melittin) on water diffusion near a single-supported zwitterionic membrane (DMPC). Measurements of the incoherent elastic neutron intensity as a function of temperature provide evidence of bulk-like water freezing onto the melittin, which AFM images indicate coalesces into peptide-lipid domains as the peptide concentration increases. Analysis of the QENS spectra indicates that, at sufficiently high melittin concentrations, a water component diffusing more slowly than bulk-like water first freezes onto the bound melittin.
Original language | English |
---|---|
Article number | 18002 |
Journal | EPL |
Volume | 123 |
Issue number | 1 |
DOIs | |
State | Published - Jul 2018 |
Funding
This work was supported by the U.S. National Science Foundation under Grant No. DGE-1069091 and utilized facilities supported in part by the NSF under agreement No. DMR-1508249. ZNB was partially supported by the U.S. Department of Energy Office of Science Graduate Student Research (SCGSR) program under contract No. DE-SC0014664. This work was supported by the U.S. National Science Foundation under Grant No. DGE-1069091 and utilized facilities supported in part by the NSF under agreement No. DMR-1508249. ZNB was partially supported by the U.S. Department of Energy Office of Science Graduate Student Research (SCGSR) program under contract No. DE-SC0014664. In situ AFM imaging was performed at the Center for Nanophase Materials Sciences, which is a DOE Office of Science User Facility. A portion of this research at Oak Ridge National Laboratory’s Spallation Neutron Source was sponsored by the Scientific User Facilities Division, Office of Basic Energy Sciences, U.S. Department of Energy. We thank Gavin King, Ioan Kosztin, and Dan Neumann for helpful discussions.