• Staff Contacts
• Program Areas
• Resource Directory
• Funding Opportunities
• Program Guidelines
• News & Events

National Biomedical Center for Advanced ESR Technology

National Biomedical Center for Advanced ESR Technology

Research Emphasis

The National Biomedical Center for Advanced ESR Technology (ACERT) is an outgrowth of extensive experience in developing the methods of modern electron spin resonance (ESR), now being disseminated to the biomedical community. In addition to making equipment and facilities available to outside scientists, publishing and advertising results, and running workshops on the new methodologies, ACERT also addresses the need to bring these new technologies to other laboratories. The center's collaborators cover a wide range of biomedical research areas, emphasizing the central role that modern ESR methods plays. The principal areas of core research are as follows:

Distance measurements in proteins and aggregates using pulsed dipolar ESR: To advance the center's knowledge of structure and function of biomolecules using longer distance constraints, provided by site-directed spin labeling and pulsed ESR distance measurements.

Pulsed two-dimensional (2-D) ESR: The development of 2D-ELDOR in the study of the dynamic structure of membranes and proteins as well as lipid-protein interactions.

Functional dynamics of proteins: The study of protein folding and unfolding and transient structural changes.

ESR microscopy: To provide micron resolution in three-dimensional imaging of biological samples.

Instrumental developments in high-frequency, high-field (HFHF) ESR: To further develop quasi-optical techniques for HFHF-ESR to unravel the complex dynamics in biological systems.

High-power pulsed HFHF ESR: To extend high-power pulsed ESR to the millimeter-wave regime, to benefit from the improved orientational resolution and faster "snapshot" feature at higher frequencies.

Multifrequency studies of dynamics: To advance knowledge of dynamics in proteins, DNA, and membranes by a mixture of multifrequency and multidimensional ESR.

Theoretical and computational methods: To improve the methods for interpreting multifrequency spectra in terms of powerful algorithms based on the stochastic Liouville equation and on molecular dynamics simulations.

Current Research

Distance measurements: Structures of protein complexes and membrane proteins. 2-D-ELDOR: Dynamics of model and biological membrane domains.

Functional dynamics: Integration of pulsed 2D-ESR with continuous and stopped-flow techniques.

ESR microscopy: Imaging microspheres for drug delivery and the imaging of cells.

HFHF ESR: Multifrequency studies of dynamics.

Pulsed HFHF ESR: High-power, 95-GHz pulsed ESR studies of dynamics in membranes and protein structure.

Resource Capabilities

Methods

ACERT occupies about 6,000 square feet of space in Baker Laboratory. It includes facilities for conducting continuous wave multifrequency ESR from 1 to 250 GHz; 2-D and Fourier transform ESR and electron-spin-echo spectrometers at 9, 17.3, 35, and 95 GHz; continuous wave and pulsed ESR microscopes; workstations for theoretical simulation of ESR spectra; wet chemistry facilities; and electronics and machining facilities.

Software

Available on Web site.

Training Opportunities and Workshops

Annual workshops announced on Web site.

Publications

1. Chiang, Y.-W., Borbat, P. P., and Freed, J. H., The determination of pair distance distributions by pulsed ESR using Tikhonov regularization. Journal of Magnetic Resonance 172:279–295, 2005.

2. Liang, Z., Lou, Y., Freed, J. H., Columbus, L., and Hubbell,W L., A multifrequency ESR study of T4 lysozyme dynamics using the slowly relaxing local structure model. Journal of Physical Chemistry 108:17649–17659, 2004.

3. Blank, A., Dunnam, C. R., Borbat, P. P., and Freed, J. H., A 3D electron spin resonance microscope. Review of Scientific Instruments 75:3050–3061, 2004.

4. Hofbauer, W., Earle, K. A., Dunnam, C. R., Moscicki, J. K., and Freed, J. H., A high-power 95 GHz pulsed ESR spectrometer. Review of Scientific Instruments 75:1194–1208, 2004.