Determination of the Distance Between Two Spin Labels Attached to a Macromolecule

An EPR "spectroscopic ruler" was developed using a series of α-helical polypeptides, each modified with two nitroxide spin labels. The EPR line broadening due to electron-electron dipolar interactions in the frozen state was determined using the Fourier deconvolution method. These dipolar...

Full description

Saved in:
Bibliographic Details
Published in:Proceedings of the National Academy of Sciences - PNAS 1995-08, Vol.92 (18), p.8239-8243
Main Authors: Rabenstein, Mark D., Shin, Yeon-Kyun
Format: Article
Language:English
Subjects:
Amino Acid Sequence
Biochemistry
Biophysics
Electron Spin Resonance Spectroscopy
Electrons
Fourier Analysis
Impurities
Macromolecules
Models, Chemical
Molecular biology
Molecular Sequence Data
Nitrogen Oxides - chemistry
Noise spectra
Peptides
Peptides - chemistry
Product labeling
Proteins
Spectral methods
Spin Labels
Tensors
Citations: Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:An EPR "spectroscopic ruler" was developed using a series of α-helical polypeptides, each modified with two nitroxide spin labels. The EPR line broadening due to electron-electron dipolar interactions in the frozen state was determined using the Fourier deconvolution method. These dipolar spectra were then used to estimate the distances between the two nitroxides separated by 8-25 Å. Results agreed well with a simple α-helical model. The standard deviation from the model system was 0.9 Å in the range of 8-25 Å. This technique is applicable to complex systems such as membrane receptors and channels, which are difficult to access with high-resolution NMR or x-ray crystallography, and is expected to be particularly useful for systems for which optical methods are hampered by the presence of light-interfering membranes or chromophores.
ISSN:0027-8424
1091-6490
DOI:10.1073/pnas.92.18.8239