+ Site Statistics
References:
54,258,434
Abstracts:
29,560,870
PMIDs:
28,072,757
+ Search Articles
+ Subscribe to Site Feeds
Most Shared
PDF Full Text
+ PDF Full Text
Request PDF Full Text
+ Follow Us
Follow on Facebook
Follow on Twitter
Follow on LinkedIn
+ Translate
+ Recently Requested

Using nitroxide spin labels. How to obtain T1e from continuous wave electron paramagnetic resonance spectra at all rotational rates



Using nitroxide spin labels. How to obtain T1e from continuous wave electron paramagnetic resonance spectra at all rotational rates



Biophysical Journal 64(3): 594-604



Historically, the continuous wave electron paramagnetic resonance (CW-EPR) progressive saturation method has been used to obtain information on the spin-lattice relaxation time (T1e) and those processes, such as motion and spin exchange, that occur on a competitive timescale. For example, qualitative information on local dynamics and solvent accessibility of proteins and nucleic acids has been obtained by this method. However, making quantitative estimates of T1e from CW-EPR spectra have been frustrated by a lack of understanding of the role of T1e (and T2e) in the slow-motion regime. Theoretical simulation of the CW-EPR lineshapes in the slow-motion region under increasing power levels has been used in this work to test whether the saturation technique can produce quantitative estimates of the spin-lattice relaxation rates. A method is presented by which the correct T1e may be extracted from an analysis of the power-saturation rollover curve, regardless of the amount of inhomogeneous broadening or the rates of molecular reorientation. The range of motional correlation times from 10 to 200 ns should be optimal for extracting quantitative estimates of T1e values in spin-labeled biomolecules. The progressive-saturation rollover curve method should find wide application in those areas of biophysics where information on molecular interactions and solvent exposure as well as molecular reorientation rates are desired.

(PDF emailed within 0-6 h: $19.90)

Accession: 009709586

Download citation: RISBibTeXText

PMID: 8386009

DOI: 10.1016/s0006-3495(93)81418-8


Related references

Use of the integral of saturation transfer electron paramagnetic resonance spectra to determine molecular rotational correlation times. Slowly tumbling spin labels in the presence of rapidly tumbling spin labels. Journal of Magnetic Resonance 44(1): 109-116, 1969

Exploring Structure, Dynamics, and Topology of Nitroxide Spin-Labeled Proteins Using Continuous-Wave Electron Paramagnetic Resonance Spectroscopy. Methods in Enzymology 564: 59-100, 2016

Magnetic resonance imaging of biological specimens by electron paramagnetic resonance of nitroxide spin labels. Science 227(4686): 517-519, 1985

Molecular distances from dipolar coupled spin-labels: the global analysis of multifrequency continuous wave electron paramagnetic resonance data. Biophysical Journal 72(4): 1861-1877, 1997

Simulating electron spin resonance spectra of nitroxide spin labels from molecular dynamics and stochastic trajectories. Journal of Chemical Physics 128(16): 165106, 2008

Simulating electron spin resonance spectra of macromolecules labeled with two dipolar-coupled nitroxide spin labels from trajectories. Physical Chemistry Chemical Physics 13(28): 12785-12797, 2012

The internal dynamics of mini c TAR DNA probed by electron paramagnetic resonance of nitroxide spin-labels at the lower stem, the loop, and the bulge. Biochemistry 51(43): 8530-8541, 2013

Integrated Computational Approach to the Electron Paramagnetic Resonance Characterization of Rigid 3 10 -Helical Peptides with TOAC Nitroxide Spin Labels. Journal of Physical Chemistry. B 121(17): 4379-4387, 2017

Computer analysis of electron paramagnetic resonance spectra of spin labels in the study of biological membranes. Biofizika 32(5): 845-858, 1987

Computational analysis of the spectra of electron paramagnetic resonance of spin labels in erythrocyte membranes in spontaneous genetic hypertension of rats. Biophysics (English Translation of Biofizika) 35(3): 462-465, 1990

Electron paramagnetic resonance of three-spin nitroxide-copper(II)-nitroxide clusters coupled by a strong exchange interaction. Journal of Physical Chemistry. a 110(7): 2315-2317, 2006

Effect of limited rotational motion on simulated conventional and saturation transfer epr spectra of nitroxide spin labels. Biophysical Journal 37(2 PART 2): 71A, 1982

Studying RNA using site-directed spin-labeling and continuous-wave electron paramagnetic resonance spectroscopy. Methods in Enzymology 469: 303-328, 2011

Saturation transfer, continuous wave saturation, and saturation recovery electron spin resonance studies of chain-spin labeled phosphatidylcholines in the low temperature phases of dipalmitoyl phosphatidylcholine bilayers. Effects of rotational dynamics and spin-spin interactions. Biophysical Journal 61(4): 879-891, 1992

The continuous wave flash photolysis electron spin resonance spectra of spin-polarized (CIDEP) radicals using time-integration spectroscopy. Molecular Physics 52(2): 431-446, 1984