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Biomedical EPR Part-B Methodology Instrumentation and Dynamics - Sandra R. Eaton

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434

SANDRA S. EATON AND GARETH R. EATON

 

Software is available, some commercially and some from individual labs

(easily locatable via the EPR Society software exchange), for simulation of many spin systems. The understanding of many spin systems is now at the stage that a full simulation of the experimental line shape is a necessary step in interpreting an EPR spectrum. There will always remain important problems for which the key is to understand the spin system, so simulation is at the edge of the state of the art. For example, for many high-spin Fe(III) systems there is little information about ZFS terms, so one does not even know which transitions should be included in the simulation. At the other extreme, for S = 1/2 organic radicals in fluid solution one should be able to fit spectra within experimental error if the radical has been correctly identified. Future directions include combining spectral interpretation as outlined above with quantum mechanical and molecular dynamics descriptions of the biological system.

The application of EPR to biological systems has become sophisticated enough, with a large arsenal of tools, each available in at least a few labs, that the main problems are now biological. That is, the EPR spectroscopy is discriminating enough that it becomes increasingly important to have a very well-defined biological system, or one will focus in great detail on an impurity, or on an ill-poised pH or redox condition. Putting “dirty” illdefined samples into the spectrometer will lead to “dirty” ill-defined ideas about what the EPR spectra mean. The spectroscopy can give very welldefined results for whatever sample happens to be put into the resonator.

As we said in the Preface, there are spins everywhere, and recognition of the importance of studying them in biological systems will increase, EPR is uniquely suited to this study. Instrumentation, methodology, software for analysis and simulation will develop in concert, simultaneously optimizing particular experiments as the horizons expand within a multi-frequency, multidimensional milieu. As electronic components with the needed capabilities become available, data acquisition will, for example, move toward direct digitization of signals so that multiple harmonics can be extracted from the raw data as outlined by Hyde in the chapter on future trends. We also envision that the EPR response region between slow-scan CW and pulsed EPR, a CW region where relaxation times affect the signal even in the absence of saturation, will increasingly be exploited. Finally, computers will be used increasingly to create new types of graphic displays to communicate multidimensional data sets to the biomedical researchers.

The focus in these two volumes has been on methodology and instrumentation. Advances in theory, and in computational methods, are also needed. Beyond these, there is an even more important element - education. There needs to be greater focus on educating the next generation of scientists who will use the powerful methods described in these volumes.

PROGNOSIS

435

That task, also, requires ingenuity and stands as a challenge to universities world-wide.

We will end this attempt at prognosis with the same hope that we ended Foundations of Modern EPR: “The most confident prediction we can make is the most exciting discoveries and enhancements will be ones we have not thought of,”

1.REFERENCES

Eaton, G. R., and Eaton, S. S. (1988a) The Future of EPR Instrumentation, Spectroscopy 3, 34-36.

Eaton, G. R., and Eaton, S. S. (1988b) Workshop on the Future of EPR (ESR) Instrumentation - Denver, Colorado, August 7,1987, Bull. Magn. Reson. 10, 3-21.

Eaton, G. R., and Eaton, S. S. (1993) The Future of Electron Paramagnetic Resonance Spectroscopy, Spectroscopy, 8 20-27.

Eaton, G. R., and Eaton, S. S. (1995) The Future of Electron Paramagnetic Resonance, Bull. Magn. Reson. 16,149-192.

Eaton, G. R., and Eaton, S. S. (1997) EPR Methodologies - Ways of Looking at Electron Spins. EPR Newsletter 9 (1), 15-18.

Eaton, G. R., Eaton, S. S., and Salikhov, K. M. (1998) The Next 50 Years, in Foundations of Modern EPR, Eaton, G. R., Eaton, S. S., and Salikhov, K. M., eds., World Scientific, Singapore, pp. 792-793.

Hassan, A. K., Pardi, L. A., Krzystek, J., Sienkiewicz, A., Goy, P., Rohrer, M., and Brunel, L.-C. (2000) Ultrawide Band Multifrequency High-Field EMR Technique: A Methodology for Increasing Spectroscopic Information. J. Magn. Reson. 142, 300-312.

Isber, S., Christidis, T., Tabbal, M., Charar, S., and Goiran, M. (2001) High-Frequency EPR of in CdSe. Physica B 293, 304-307.

Motokawa, M. (2000) Electron Spin Resonance of Magnetic Materials in High Fields and High Frequencies. Appl. Magn. Reson. 19, 77-91.

Rinard, G. A., Quine, R. W., Ghim, B. T., Eaton, S. S., and Eaton, G. R. (1996a) Easily Tunable Crossed-Loop (Bimodal) EPR Resonator, J. Magn. Reson. A 122, 50-57.

Rinard, G. A., Quine, R. W., Ghim, B. T., Eaton, S. S., and Eaton, G. R. (1996b) Dispersion and Superheterodyne EPR Using a Bimodal Resonator, J. Magn. Reson. A 122, 58-63.

Rinard, G. A., Quine, R. W., Song, R., Eaton, G. R,. and Eaton, S. S. (1999) Absolute EPR Spin Echo and Noise Intensities, J. Magn. Reson. 140, 69-83.

Rinard, G. A., Quine, R. W., Eaton, S. S., Eaton, G. R., Barth, E. D., Pelizzari, C. A., and Halpern, H. H. (2002) Magnet and Gradient Coil System for Low-Field EPR Imaging,

Magn. Reson. Engineer. 15, 51-58.

Rinard, G. A., Quine, R. W., Eaton, G. R., and Eaton, S. S. (2002) 250 MHz Crossed Loop Resonator for Pulsed Electron Paramagnetic Resonance, Magn. Reson. Engineer. 15, 37-

46.

Contents of Previous Volumes

VOLUME 1

Chapter 1

NMR of Sodium-23 and Potassium-39 in Biological Systems

Mortimer M. Civan and Mordechai Shporer

Chapter 2

High-Resolution NMR Studies of Histones

C. Crane-Robinson

Chapter 3

PMR Studies of Secondary and Tertiary Structure of Transfer RNA in Solution

Philip H. Bolton and David R. Kearns

Chapter 4

Fluorine Magnetic Resonance in Biochemistry

J. T. Gerig

Chapter 5

ESR of Free Radicals in Enzymatic Systems

Dale E. Edmondson

437

438

Contents of Previous Volumes

Chapter 6

Paramagnetic Intermediates in Photosynthetic Systems

Joseph T. Warden

Chapter 7

ESR of Copper in Biological Systems

John F. Boas, John R. Pilbrow, and Thomas D. Smith

VOLUME 2

Chapter 1

Phosphorus NMR of Cells, Tissues, and Organelles

Donald P. Hollis

Chapter 2

EPR of Molybdenum-Containing Enzymes

Robert C. Bray

Chapter 3

ESR of Iron Proteins

Thomas D. Smith and John R. Pilbrow

Chapter 4

Stable Imidazoline Nitroxides

Leonid B. Volodarsky, Igor A. Grigor’ev, and Renad Z. Sagdeev

Chapter 5

The Multinuclear NMR Approach to Peptides: Structures, Conformation, and Dynamics

Roxanne Deslauriers and Ian C. P. Smith

VOLUME 3

Chapter 1

Multiple Irradiation NMR Experiments with Hemoproteins

Regula M. Keller and Kurt Wüthrich

Contents of Previous Volumes

439

Chapter 2

Vanadyl(IV) EPR Spin Probes: Inorganic and Biochemical Aspects

N. Dennis Chasteen

Chapter 3

ESR Studies of Calciumand Protein-Induced Photon Separations in Phospatidylserine-Phosphatidylcholine Mixed Membranes

Shun-ichi Ohnishi and Satoru Tokutomi

Chapter 4

EPR Crystallography of Metalloproteins and Spin-Labeled Enzymes

James C. W. Chien and L. Charles Dickinson

Chapter 5

Electron Spin Echo Spectroscopy and the Study of Metalloproteins

W. B. Mims and J. Peisach

VOLUME 4

Chapter 1

Spin Labeling in Disease

D. Allan Butterfield

Chapter 2

Principles and Applications of NMR to Biological Systems

Ian M. Armitage and James D. Otvos

Chapter 3

Photo-CIDNP Studies of Proteins

Robert Kaptein

Chapter 4

Application of Ring Current Calculations to the Proton NMR of Proteins and Transfer RNA

Stephen J. Perkins

440

Contents of Previous Volumes

VOLUME 5

Chapter 1

CMR as a Probe for Metabolic Pathways in Vivo

R. L. Baxter, N. E. Mackenzie, and A. I. Scott

Chapter 2

Nitrogen-15 NMR in Biological Systems

Felix Blomberg and Heinz Rüterjans

Chapter 3

Phosphorus-31 Nuclear Magnetic Resonance Investigations of Enzyme

Systems

B. D. Nageswara Rao

Chapter 4

NMR Methods Involving Oxygen Isotopes in Biophosphates

Ming-Daw Tsai and Larol Bruzik

Chapter 5

ESR and NMR Studies of Lipid-Protein Interactions in Membranes

Philippe F. Devaux

VOLUME 6

Chapter 1

Two-Dimensional Spectroscopy as a Conformational Probe of Cellular

Phosphates

Philip H. Bolton

Chapter 2

Lanthanide Complexes of Peptides and Proteins

Robert E. Lenkinski

Chapter 3

EPR of Mn(II) Complexes with Enzymes and Other Proteins

George H. Reed and George D. Markham

Contents of Previous Volumes

441

Chapter 4

Biological Applications of Time Domain ESR

Hans Thomann, Larry R. Dalton, and Lauraine A. Dalton

Chapter 5

Techniques, Theory, and Biological Applications of Optically Detected Magnetic Resonance (ODMR)

August H. Maki

VOLUME 7

Chapter 1

NMR Spectroscopy of the Intact Heart

Gabriel A. Elgavish

Chapter 2

NMR Methods for Studying Enzyme Kinetics in Cells and Tissue

K. M. Brindle, I. D. Campbell, and R. J. Simpson

Chapter 3

Endor Spectroscopy in Photobiology and Biochemistry

Klaus Möbius and Wolfgang Lubitz

Chapter 4

NMR Studies of Calcium-Binding Proteins

Hans J. Vogel and Sture Forsén

VOLUME 8

Chapter 1

Calculating Slow Motional Magnetic Resonance Spectra: A User’s Guide

David J. Schneider and Jack H. Freed

Chapter 2

Inhomogeneously Broadened Spin-Label Spectra

Barney Bales

442

Contents of Previous Volumes

Chapter 3

Saturation Transfer Spectroscopy of Spin-Labels: Techniques and

Interpretation of Spectra

M. A. Hemminga and P. A. de Jager

Chapter 4

Nitrogen-15 and Deuterium Substituted Spin Labels for Studies of Very Slow Rotational Motion

Albert H. Beth and Bruce H. Robinson

Chapter 5

Experimental Methods in Spin-Label Spectral Analysis

Derek Marsh

Chapter 6

Electron-Electron Double Resonance

James S. Hyde and Jim B. Feix

Chapter 7

Resolved Electron-Electron Spin-Spin Splittings in EPR Spectra

Gareth R. Eaton and Sandra S. Eaton

Chapter 8

Spin-Label Oximetry

James S. Hyde and Witold S. Subczynski

Chapter 9

Chemistry of Spin-Labeled Amino Acids and Peptides: Some New Monoand Bifunctionalized Nitroxide Free Radicals

Kálmán Hideg and Olga H. Hankovsky

Chapter 10

Nitroxide Radical Adducts in Biology: Chemistry, Applications, and

Pitfalls

Carolyn Mottley and Ronald P. Mason

Contents of Previous Volumes

443

Chapter 11

Advantages of and Deuterium Spin Probes for Biomedical Electron Paramagnetic Resonance Investigations

Jane H. Park and Wolfgang E. Trommer

Chapter 12

Magnetic Resonance Study of the Combining Site Structure of a Monoclonal Anti-Spin-Label Antibody

Jacob Anglister

Appendix

Approaches to the Chemical Synthesis of and Deuterium Substituted Spin Labels

Jane H. Park and Wolfgang E. Trommer

VOLUME 9

Chapter 1

Phosphorus NMR of Membranes

Philip L. Yeagle

Chapter 2

Investigation of Ribosomal 5S Ribonucleotide Acid Solution Structure and Dynamics by Means of High-Resolution Nuclear Magnetic Resonance Spectroscopy

Alan G. Marshall and Jiejun Wu

Chapter 3

Structure Determination via Complete Relaxation Matrix Analysis (CORMA) of Two-Dimensional Nuclear Overhauser Effect Spectra: DNA Fragments

Brandan A. Borgias and Thomas L. James

Chapter 4

Methods of Proton Resonance Assignment for Proteins

Andrew D. Robertson and John L. Markley

444

Contents of Previous Volumes

Chapter 5

Solid-State NMR Spectroscopy of Proteins

Stanley J. Opella

Chapter 6

Methods for Suppression of the Signal in Proton FT/NMR Spectroscopy: A Review

Joseph E. Meier and Alan G. Marshall

VOLUME 10

Chapter 1

High-Resolution Magnetic Resonance Spectroscopy of

Oligosaccharide-Alditols Released from Mucin-Type O-Glycoproteins

Johannis P. Kamerling and Johannes F. G. Vliegenthart

Chapter 2

NMR Studies of Nucleic Acids and Their Complexes

David E. Wemmer

VOLUME 11

Chapter 1

Localization of Clinical NMR Spectroscopy

Lizann Bolinger and Robert E. Lenkinski

Chapter 2

Off-Resonance Rotating Frame Spin-Lattice Relaxation: Theory, and in Vivo MRS and MRI Applications

Thomas Schleich, G. Herbert Caines, and Jan M. Rydzewski

Chapter 3

NMR Methods in Studies of Brain Ischemia

Lee-Hong Chang and Thomas L. James