Home > Research > Biotechnology Resource Centers
E-mail this page 
 |
|
W-band loop gap resonator design for use with aqueous samples. The low Q and high efficiency parameters favor pulse experiments.
|
|
National Biomedical Electron Paramagnetic Resonance Center
Contents
Contact Information
Principal Investigator/Contact
James S. Hyde, Ph.D.
Phone: 414-456-4000
Fax: 414-456-6512
jshyde@mcw.edu
Contact
Christopher C. Felix, Ph.D.
Phone: 414-456-4008
Fax: 414-456-6512
Grant Number
Grant No. EB001980
Research Emphasis
- Development of multiquantum Q- and W-band spectrometers, including multiquantum ELDOR, development of time-locked sub-sampling (TLSS) for broadband detection of periodically modulated signals
- Development of loop-gap resonators using finite element modeling of Maxwell's equations
- Application of multifrequency (1 to 100 GHz) electron paramagnetic resonance (EPR) to characterize paramagnetic centers
- Study of relaxation processes using multifrequency pulse saturation recovery
- Use of nitroxide radical spin labels to measure translational and rotational diffusion in biological systems, site-directed spin labeling (SDSL), and use of EPR for the detection of nitric oxide and oxy radicals
Current Research
Physical studies of nitroxide radical spin labels, measurement of spin label T1s, diffusion processes in synthetic and biological membranes, oxygen transport in and across model membranes, discrimination of membrane domains and their physical characterization in situ, EPR characterization of immobilized free radicals, structure of ferric enterobactin receptor (FepA), and characterization of antibiotic peptide-membrane interactions using SDSL methods, structure-function studies on a bacterial ABC lipid A transporter and previously uncharacterized bacterial membrane protein involved in antibiotic resistance, spin trapping and spin stabilization of oxygen-centered free radicals, spin-trap assays for nitric oxide, EPR investigation of nitric oxide synthase, study of nitric oxide-hemoglobin interactions, copper ligation and charge in copper proteins including prions, characterization of the substrate binding pocket of an animopeptidase, mechanisms of metallohydrolases, and characterization of higher-order effects occurring in transition-metal spectra measured with lower frequency microwaves.
An advanced Q-band spectrometer has been developed with the following capabilities: CW EPR, pulse saturation recovery, pulse ELDOR, multiquantum EPR, and multiquantum ELDOR, all with detection by time-locked sub-sampling. Initiatives are underway to extend these capabilities to W-band by frequency translation. Novel W-band resonators are under development.
Resource Capabilities
Instruments
- Bruker ELEXSYS EPR Spectrometer System for ambient and liquid nitrogen temperatures
- Bruker ELEXSYS System with X-band and Q-band EPR and ENDOR at 4-295 K°
- Bruker E-600 W-Band CW-EPR (including W-band cylindrical resonator, W-band bridge, superconducting magnet, room temperature sweep coils and cryostat)
- Varian E-109 Century Series EPR Spectrometer (2)
- Bruker EMX Spectrometer
- Varian E-9 EPR Multifrequency Spectrometer
- Time-Domain ESR Spectrometer at 9 GHz with 9 inch Magnet
- Multifrequency Time-Domain EPR Spectrometer with 10 inch Bruker Magnet
- Multiquantum X-Band EPR Spectrometer with 9 inch Jagmar Magnet
- Multiquantum Q-Band Spectrometer with 10 inch Bruker Magnet
- Rapid Freeze Quench (RFQ)
Software Resources
- Ansoft High Frequency Structure Simulator (HFSS) and Computer Simulation Technology (CST) Microwave Studio permit objective (rather than intuitive) design of loop-gap resonator coils and are useful for modeling RF field distributions.
- Ansoft Maxwell 3D
- Bruker Xsophe program for simulation and analysis of isotropic, randomly oriented and single crystal CW EPR spectra
Microwave Test Equipment
- Agilent E5501B Phase Noise Measurement System
- E8363B Network Analyzer with Oleson V10VNA2-T/R W-band heads (45 MHz-40 GHz and 75-100 GHz)
- HP8722D Network Analyzer (50 MHz-40 GHz)
- HP8566B Spectrum Analyzer (100 Hz-22 GHz to 100 GHz with external mixers)
- HP8596E Spectrum Analyzer (9 KHz-12.8 GHz)
- HP8564E Spectrum Analyzer (9 KHz-40 GHz)
Back to Top
References
- Subczynski WK, Kusumi A. Dynamics of raft molecules in the cell and artificial membranes: approaches by pulse EPR spin labeling and single molecule optical microscopy. Biochim. Biophys. Acta 2003;1610:231-243. Full text
- Burns CS, Aronoff-Spencer E, Legname G, Prusiner SB, Antholine WE, Gerfen GJ, Peisach J, Millhauser GL. Molecular features of the copper coordination sites in the full-length, recombinant prion protein. Biochemistry 2003;42(22):6794-6803.
- Bhargava K, Feix JF. Membrane binding, structure, and localization of cecropin-mellitin hydrid peptides: a site-directed spin-labeling tudy. Biophys J 2004;86:329-336.
- Mett RR, Hyde JS. Aqueous flat cells perpendicular to the electric field for use in electron paramagnetic resonance spectroscopy. J. Magn. Reson. 2003;165:137-152. Adobe PDF (343K)
- Bennett B. EPR of Co(II) as a structural and mechanistic probe of metalloprotein active sites: characterisation of an aminopeptidase. Current Topics in Biophysics 2002;26:49-57. Adobe PDF (1.25M)
|
