SS2014 Modern Methods in Experimental Physics

MTSL rotamers
MTSL rotamers

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 a lab course may be offered (to be decided with the students) on continuous wave or pulsed EPR techniques.

Lectures: Mondays 16-18 in  1.3.21 Seminarraum T1

Slides and additional material can be found here (registered students: please send me an e-mail and you will get access)

Lecture Material
14.04 Introduction to proteins and SDSL EPR
12.05 Description of a CW EPR spectrometer

Simulation of the effects of overmodulation on the lineshape

(and experimental comparison)

Introduction on chemical exchange


g- and A- anisotropy


Material praktikum DEER

problem, solution, praktikum description,

detailed description of a DEER setup

Exercises: Mondays 14-16 in 1.3.21 Seminarraum T1. Note that on 28.04.2014 there will be no exercises. The exercises will start on 05.05.2014.

ex. number exercise online hand in by

solution online

ex_01 28.04.2014 05.05.2014 (10 am) 05.05.2014 sol_01
ex_02 05.05.2014 12.05.2014 (10 am) 12.05.2014 sol_02
ex_03 02.06.2014 16.06.2014 (10 am) 16.06.2014 sol_03

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.