A5006256457- Lipid Membrane Structure and Behavior
- Spectroscopy and Quantum Chemical Studies
- Protein Structure and Dynamics
- Sphingolipid Metabolism and Signaling
- Nanopore and Nanochannel Transport Studies
- Surfactants and Colloidal Systems
- Immune Response and Inflammation
- Magnetic and Electromagnetic Effects
- Origins and Evolution of Life
- Cholesterol and Lipid Metabolism
- Food Supply Chain Traceability
- Enzyme Structure and Function
- Surface and Thin Film Phenomena
- Magnetic properties of thin films
- Plant and Biological Electrophysiology Studies
- Information Retrieval and Data Mining
- Semiconductor materials and interfaces
- NMR spectroscopy and applications
- Alzheimer's disease research and treatments
- RNA and protein synthesis mechanisms
- Photoreceptor and optogenetics research
- Plant Genetic and Mutation Studies
McMaster University
2012-2015
ABB (Switzerland)
2015
Lakehead University
2006
One of the hallmarks Alzheimer's disease is formation senile plaques, primarily consisting amyloid- (A) peptides. Peptide-membrane and peptide-lipid interactions are thought to be crucial in this process. We studied interaction A peptides with anionic lipid membranes made dimyristoylphosphatidylcholine (DMPC) dimyristoylphosphoserine (DMPS) using X-ray diffraction. compare experimentally determined electron densities gel state density calculations from peptide structures reported Protein...
Rafts, or functional domains, are transient nano- mesoscopic structures in the plasma membrane and thought to be essential for many cellular processes such as signal transduction, adhesion, trafficking lipid/protein sorting. Observations of these heterogeneities have proven challenging, they both small short-lived. With a combination coarse-grained molecular dynamics simulations neutron diffraction using deuterium labeled cholesterol molecules we observe raft-like determine ordering binary...
A fundamental question of biology is how nucleic acids first assembled and then were incorporated into the earliest forms cellular life 4 billion years ago. The polymerization nucleotides a condensation reaction in which phosphodiester bonds are formed. This cannot occur aqueous solutions, but guided an anhydrous lipid environment could promote non-enzymatic oligomers single stranded synthesized. We used X-ray scattering to investigate 5′-adenosine monophosphate (AMP) molecules captured...
The molecular in-plane and out-of-plane structure of dimyristoylphosphatidylcholine (DMPC) membranes containing up to 60 mol% cholesterol was studied using X-ray diffraction. Up 37.5 could be dissolved in the membranes, resulting a disordered lateral membrane structure. Highly ordered structures were observed at concentrations more than 40 cholesterol. These characterized as immiscible plaques, i.e., bilayers molecules coexisting with lipid bilayer. found form monoclinic cholesterol, which...
The presence of cholesterol in lipid membranes with ibuprofen suppresses partitioning the tail groups and stabilizes lamellar membrane phases.
We present a combined neutron and X-ray scattering investigation to study the effect of ethanol on molecular structure dynamics lipid membranes. 1,2-Dimyristoyl-sn-glycero-3-phoshatidylcholine (DMPC) powder hydrated with 5 wt% solution (corresponding 2 mol% ethanol) was used in this study. From high-resolution experiments position partitioning molecules phospholipid bilayers determined their gel fluid phases. find that reside head group region bilayers, 1.6 per molecule phase 1.2 phase....
Lateral nanostructures in membranes, so-called rafts, are believed to strongly influence membrane properties and functions. The experimental observation of rafts has proven difficult as they thought be dynamic structures that likely fluctuate on nano- microsecond time scales. Using neutron diffraction we present direct evidence for the co-existence gel fluid lipid domains a single-component phospholipid made DPPC it undergoes its main phase transition. coherence length beam sets lower limit...
We have studied nanoscale diffusion of membrane hydration water in fluid-phase lipid bilayers made 1,2-dimyristoyl-3-phosphocholine (DMPC) using incoherent quasi-elastic neutron scattering. Dynamics were fit directly the energy domain Fourier transform a stretched exponential. By large, 2-dimensional detectors, lateral motions molecules and perpendicular to membranes could be simultaneously, resulting maps relaxation time, τ, stretching exponent, β. present experimental evidence for...
We studied molecular order in native plant plasma membranes the presence of static magnetic fields. Plasma seeds tomato were purified, extracted, and applied to a silicon substrate buffer suspension their structure was using X-ray diffraction. observed correlation peaks that we assigned lipid protein components membrane. Two field strengths available: B = 0.126 T 0.208 T. While fields had no observable effect on structure, enhanced observed, leading an increase gel decrease fluid component lipids.
Diffusion is the fundamental mechanism for lipids and other molecules to move in a membrane. It an important process consider modelling formation of membrane structures, such as rafts. Lipid diffusion mainly studied by two different techniques: incoherent neutron scattering fluorescence microscopy. Both techniques access distinctly length scales. While measures over about 3 lipid diameters, microscopic motions micrometer distances. The constants which are determined these methods often...
We present a high-temperature and high-energy resolution neutron scattering investigation of hydration water freezing in single supported lipid bilayers. Single bilayers provide well-defined biological interface to study dynamics coupling membrane degrees freedom. Nanosecond molecular motions were studied the temperature range 240 K < T 290 slow heating cooling cycles using coherent incoherent elastic on backscattering spectrometer. Several melting transitions observed. From length scale...
Abstract For the past 100 years, X-ray diffraction has been a powerful and indispensable tool to study structure of matter. The challenge when studying molecular ordering in biological materials is their inherent disorder strong fluctuations, which often suppress formation Bragg peaks. In case membranes, X-rays can detect molecules inside confined between membranes. this article we review examples highlight capabilities accomplishments scattering for determination membrane structure. gives...
For decades, quasi-elastic neutron scattering has been the prime tool for studying molecular diffusion in membranes over relevant nanometer distances. These experiments are essential to our current understanding of dynamics lipids, proteins and membrane-active molecules. Recently, we presented experimental evidence from X-ray diffraction demonstrating that ethanol enhances permeability membranes. At QENS 2014/WINS 2014 conference a novel technique measure across employing 2-dimensional...