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Methods and applications of site-directed spin labeling EPR spectroscopy. Methods Cell Biol 2008;84:617-58



Pubmed ID




Scopus ID

2-s2.0-35448961949   119 Citations


Site-directed spin labeling (SDSL) electron paramagnetic resonance (EPR) spectroscopy has emerged as a well-established method that can provide specific information on the location and environment of an individual residue within large and complex protein structures. The SDSL technique involves introducing a cysteine residue at the site of interest and then covalently labeling with a sulfhydryl-specific spin label containing a stable free radical, which is used as the EPR-detectable probe. SDSL directly probes the local environment, structure, and proximity of individual residues, and is often greatly advantageous over techniques that give global information on protein structure and changes. SDSL can detect and follow changes in local structure due to intramolecular conformational changes or dynamic interactions with other proteins, peptides, or substrates. In addition, this technique can detect changes in distances between two sites and provide information on the depth of spin labels located within a membrane bilayer. EPR is neither limited by the size of the protein or peptide nor limited by the optical properties of the sample and has the unique ability to address and answer structure and dynamics questions that are not solvable solely by genetic or crystal structure analysis, making it highly complementary to other structural methods. In this chapter, we introduce the basic methods for using SDSL EPR spectroscopy in the study of the structure and dynamics of proteins and peptides and illustrate the practical applications of this method through specific examples in the literature.

Author List

Klug CS, Feix JB


Jimmy B. Feix PhD Professor in the Biophysics department at Medical College of Wisconsin
Candice S. Klug PhD Professor in the Biophysics department at Medical College of Wisconsin

MESH terms used to index this publication - Major topics in bold

Electron Spin Resonance Spectroscopy
Escherichia coli
Protein Binding
Protein Folding
Protein Structure, Secondary
Spin Labels
jenkins-FCD Prod-468 69a93cef3257f26b866d455c1d2b2d0f28382f14