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WS 14/15 Modern Methods in Experimental Physics

Site-directed spin labeling EPR

The course gives an introduction to electron paramagnetic resonance (EPR) spectroscopy, with special focus on site-directed spin labeling (SDSL) for the study of biomolecules. SDSL EPR is a biophysical technique providing structural and dynamic information on proteins to bridge the gap between the static snapshot of a crystal structure and the protein’s dynamic nature in a physiological environment. At the beginning of the course a brief introduction on amino acids and protein's primary-tertiary structures will be provided. The course will then start from a general description of the magnetic resonance phenomena: classical description and Bloch equations, quantum description of the spin system, spin Hamiltonian, density operators, product operator formalism (spin 1/2). The nitroxide-based spin labels available for protein studies are presented and the properties of their continuous wave EPR spectra are described in detail with focus on the dynamics and polarity effects on the spectral features and the multi-frequency advantage. Continuous wave and pulsed methods to measure interspin distances are described. A schematic description of continuous wave and pulsed spectrometers is given. State of the art applications of SDSL EPR to water soluble and membrane proteins are presented at the end of the course.

Exercises will cover the theoretical aspects presented in the course and two lab courses may be offered (to be decided with the students) on continuous wave or pulsed EPR techniques.

Lectures: Mondays from 12:00 to 14:00 in room 1.1.16

Slides and additional material will be provided during the lecture. Selected material can be also found here (registered students: please send me an e-mail and you will get access)
Lecture Material

 Introduction: why using EPR to study proteins?



10/11 Exchange phenomena
08/12 Spins of metals

Single crystal and g tensor

Direct product for coupled spins

Lecture notes

15/12 Nuclear isotope database (from Easyspin)
05/01 H_hf_nq_zfs
12/01 H_exch_dip
19/01 Product_Operator_Formalism



Exercises: Tuesdays from 14:00 to 16:00 in room 1.1.16. Note that on 14/10/2014 there will be no exercises. The exercises will start on 21/10/2014.

Exercises and solutions will be available here. (Registered students: please send me an e-mail and you get access)

ex. number exercise online hand in by

solution online

ex_01  22.10.2014  27.10.2014  sol_1
ex_02  30.10.2014  03.11.2014  sol_2
 praktikum CW EPR    16.12 12:00-18:00       Room 0.4.40
 ex_03  27.11.2014  01.12.2014  sol_3
ex_04 22.01.2015 02.02.2015  sol_4
praktikum DEER 06.02.2015 11:00-19:00 Room 0.4.40
ex_05 sol_05

if you are interested in the EPR summer school 2015: http://www.helmholtz-berlin.de/events/efepr/index_de.html

Suggested readings:


- Lehninger Principles of Biochemistry. By: David L. Nelson, Michael M. Cox. Chapters on: Amino acids, peptides and proteins & The three-dimensional structure of proteins

-"Structure validation by Calpha geometry: phi, psi and Cbeta deviation". Lovell et al. Proteins 2003, 50(3):437-50.

General Magnetic Resonance Theory

- Principles of Magnetism. A. Abragam. Oxford Science Publication.

- Principles of pulse electron paramagnetic resonance. A. Schweiger, G. Jeschke.Oxford University Press.

EPR spectrometers

-Electron Spin Resonance: a comprehensive treatise on experimental Techniques. C. P. Poole. Courier Dover Publications, 1996.


-EPR Spectroscopy. Applications in Chemistry and Biology. Topics in Current Chemistry 321. Eds. M. Drescher, G. Jeschke. Springer

-ESR Spectroscopy in membrane Biophysics. Eds. M.A. Hemminga,L.J. Berliner. Springer.