A5085160326- Advanced NMR Techniques and Applications
- Photoreceptor and optogenetics research
- Solid-state spectroscopy and crystallography
- NMR spectroscopy and applications
- Lipid Membrane Structure and Behavior
- Electron Spin Resonance Studies
- Neuroscience and Neuropharmacology Research
- Protein Structure and Dynamics
- Molecular spectroscopy and chirality
- Supramolecular Self-Assembly in Materials
- Spectroscopy and Quantum Chemical Studies
- Advanced MRI Techniques and Applications
- Alzheimer's disease research and treatments
- Photosynthetic Processes and Mechanisms
- Ion Transport and Channel Regulation
- Atomic and Subatomic Physics Research
- DNA and Nucleic Acid Chemistry
- Quantum Dots Synthesis And Properties
- Advanced Neuroimaging Techniques and Applications
- RNA and protein synthesis mechanisms
- Semiconductor Quantum Structures and Devices
- Quantum and electron transport phenomena
- Bone and Dental Protein Studies
- Origins and Evolution of Life
- Glycosylation and Glycoproteins Research
University of Guelph
2016-2025
Massachusetts Institute of Technology
2002-2013
Massey University
2010
Weizmann Institute of Science
1997-2003
Leiden University
2000
The cross-β amyloid form of peptides and proteins represents an archetypal widely accessible structure consisting ordered arrays β-sheet filaments. These complex aggregates have remarkable chemical physical properties, the conversion normally soluble functional forms into structures is linked to many debilitating human diseases, including several common age-related dementia. Despite their importance, however, fibrils proved be recalcitrant detailed structural analysis. By combining...
Magic angle spinning (MAS) NMR structure determination is rapidly developing. We demonstrate a method to determine 1H−13C distances r CH with high precision from Lee−Goldburg cross-polarization (LG-CP) fast MAS and continuous LG decoupling on uniformly 13C-enriched tyrosine·HCl. The sequence γ-encoded, spin-pair interactions are predominantly responsible for the polarization transfer while proton spin diffusion prevented. When CP amplitudes set sideband of Hartmann−Hahn match condition,...
Break on through: High-resolution multidimensional solid-state NMR spectroscopy was used to refine the molecular conformation of a seven-helical transmembrane photoreceptor in lipids (see picture, right). H/D exchange experiments left; black spectrum: H2O, red D2O) reveal solvent-exposed surface protein, which is asymmetrically positioned bilayer.
We used high-resolution proton-detected multidimensional NMR to study the solvent-exposed parts of a seven-helical integral membrane proton pump, proteorhodopsin (PR). PR samples were prepared by growing apoprotein on fully deuterated medium and reintroducing protons solvent-accessible sites through exchange with protonated buffer. This preparation leads spectra resolution down ca. 0.2 ppm at fast spinning (28 kHz) in protein back-exchanged level 40%. Novel three-dimensional chemical shift...
Protein magic angle spinning (MAS) NMR spectroscopy has generated structural models of several amyloid fibril systems, thus providing valuable information regarding the forces and interactions that confer extraordinary stability architecture. Despite these advances, however, obtaining atomic resolution describing higher levels organization within fibrils remains a significant challenge. Here, we detail MAS experiments sample labeling schemes designed specifically to probe such order...
The ability to detect and characterize molecular motions represents one of the unique strengths nuclear magnetic resonance (NMR) spectroscopy. In this study, we report solid-state NMR site-specific measurements dipolar order parameters (15)N rotating frame spin-lattice (R1ρ) relaxation rates in a seven transmembrane helical protein Anabaena Sensory Rhodopsin reconstituted lipids. magnitudes observed indicate that both well-defined regions less structured intramembrane loops undergo...
Protein-protein interactions play critical roles in cellular function and oligomerization of membrane proteins is a commonly observed phenomenon. Determining the state defining intermolecular interface bilayer generally difficult task. Here, we use site-specific spin labeling to demonstrate that relaxation enhancements induced by covalently attached paramagnetic tag can provide distance restraints intermonomer oligomers formed seven-helical transmembrane protein Anabaena Sensory Rhodopsin...
This paper presents a theoretical description of continuous wave (CW) high frequency Lee–Goldburg cross polarization magic angle spinning (LG–CPMAS) nuclear magnetic resonance experiments. The full time-dependent LG–CPMAS Hamiltonian is replaced by its zero order time-independent in the interaction representation. Carbon signal enhancements experiments are calculated for spin systems consisting six H1 nuclei coupled to one C13 nucleus. These simulations based on Floquet theory calculations,...
Dynamic nuclear polarization (DNP) enhances the signal in solid-state NMR of proteins by transferring from electronic spins to interest. Typically, both protein and an exogenous source spins, such as a biradical, are either codissolved or suspended then frozen glycerol/water glassy matrix achieve homogeneous distribution. While use protects upon freezing, it also reduces available sample volume (by ca. factor 4 our experiments) causes proportional loss. Here we demonstrate alternative...
CdS and CdS:Mn nanoparticles were studied by 113Cd proton NMR. Nanoparticle samples synthesized precipitation of from an aqueous solution Na2S CdSO4. The not deliberately capped any surface-termination agent. NMR spectra prepared with excess Cd consist three frequency bands: a bulk line corresponding to the inner atoms full sulfur coordination, broad band due surface atoms, sharp CdSO4 in solution. assignment these lines is accomplished experiments on S-rich samples, study temperature...
Cellular membranes are natural nanoengineering devices, where matter transport, information processing, and energy conversion across the nanoscale boundaries mediated by membrane proteins (MPs). Despite great potential of MPs for nanotechnologies, their broad utility in engineered systems is limited fluidic often labile nature MP-supporting membranes. Little known on how to direct spontaneous reconstitution into robust synthetic nanomembranes or tune MP functions through rational design...
Proteins are dynamic entities and populate ensembles of conformations. Transitions between states within a conformational ensemble occur over broad spectrum amplitude time scales, often related to biological function. Whereas solid-state NMR (SSNMR) spectroscopy has recently been used characterize proteins in the microcrystalline states, its applications membrane remain limited. Here we use SSNMR study dynamics seven-helical transmembrane (TM) protein, Anabaena Sensory Rhodopsin (ASR)...