COLL 51 |
| Canay Ege1, Jaroslaw Majewski2, Guohui Wu1, Kristian Kjaer3, Sushil K. Satija4, and Ka Yee C. Lee1. (1) Department of Chemistry, The Institute for Biophysical Dynamics & The James Franck Institute, The University of Chicago, 5735 S. Ellis Avenue, Chicago, IL 60637, (2) LANSCE, Los Alamos National Labs, Los Alamos, NM 87545, (3) Condensed Matter Physics and Chemistry Department, Risų National Laboratory, Denmark, Roskilde, DK-4000, Denmark, (4) Center for Neutron Research, NIST, 100 Bereau Dr. STOP 8562, Gaithersburg, MD 20854 |
| The beta amyloid peptide (Ab), a 40 to 43 residue peptide, is the major component found in the amyloid aggregates in Alzheimer's Disease patients. In vitro cell culture studies have shown that Ab is to xic to neurons and that toxicity maay associated with the oligomers or aggregates. However, such in vitro studies have to employ supraphysiological concentrations of up to millimolar Ab for short periods of time, whereas the i n vivo deposition of Ab evolves over long periods of time by the production of nanomolar concentrations in the brain. It is more informative, therefore, to look at the interactions of the peptide with lipid membranes, because the presence of phospholipids has been shown to induce the aggregation of A b at micromolar concentrations. Using X-ray reflectivity (XR), grazing incidence X-ray diffraction (GIXD), and neutron reflectivity (NR), we have studied t he interaction between Ab 40 with the following Langmuir monolayers: anionic DPPG, cationic DPTAP, and zwitterionic DPPC. With XR and NR techniques we were able to work out the composition profile of the monolayer perpendicular to the interface. With GI XD, we have information on the two-dimensional ordering of the monolayer, and how it changes upon the introduction of Ab40. |
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Nanoscale Imaging of Biological Systems
Division of Colloid and Surface Chemistry |