Hyperfine spectroscopy

Keyvrords CW EPR spectroscopy Dynamics ENDOR ESEEM Hyperfine spectroscopy In-cell EPR Nucleic acids PELDOR RNA-ligand interactions RNA-protein interactions Stmcture... 

A third contribution of importance in hyperfine spectroscopy is the nuclear quadrupole moment for nuclei with I > 1/2, e.g., H, N, and They lead to an additional line broadening, arising from the shift of the nuclear spin eigenstates by the quadrupolar coupling ... 

Characterization of Metal Ion Binding Sites by Hyperfine Spectroscopy... 

Hyperfine spectroscopy methods, such as ID ESEEM, 2D HYSCORE, and ENDOR, have been employed to determine the coordination sphere of Mn " ions bound to the HHRz or to the Diels-Alder ribozyme. The HHRz was first investigated by X-band stimulated echo ESEEM by Britt and coworkers [102]. The ESEEM data revealed nitrogen hyperfine coupling of 2.3 MHz,... 

Fig. 12 Summary of hyperfine spectroscopy results on Mn bound to HHRz. Top right. Q-band phosphor ENDOR showing a hyperfine splitting consistent with a inner-sphere coordination to the phosphor-diester oxygen. Lower right Fourier transform of X-band ESEEM measurements showing the coordination to the nitrogen of dGlO.l. Lower left. X-band ESEEM spectroscopy of HHRz in deuterated water. A quantitative comparison with simulations allows to determine the number of coordinated water molecules. Figure adapted from [106] with permission of the journal...

The variety of structural elements and the flexibility of NA molecules require both structural and dynamic methods for a functional characterization. As shown in this chapter, dipolar and hyperfine spectroscopy are important tools to determine short and long range distance constraints on such molecules. CW EPR can probe the dynamical behavior of NA molecules under physiological conditions and bridge the gap to the frozen-in conformational states, reflected by the distance distribution functions from low-temperature PELDOR experiments. The assortment of spin labels and spin-labeled positions in NAs offer the unique opportunity to place the... 

J.L. Hall, Sub-Doppler spectroscopy, methane hyperfine spectroscopy and the ultimate resolution limit, in Colloq. Int. due CNRS, vol. 217 (Edit, due CNRS, Paris, 1974), p. 105... 

R. Jacquinot, R. Klapisch, Hyperfine spectroscopy of radioactive atoms. Rep. Prog. Phys. 

The existence of a proper y-ray transition is an outcome of nuclear structure. Therefore, a Mdssbauer transition is coupled to a certain isotope of the atom of interest. A low isotopic abundance of the resonant isotope may be a serious restriction. Next, if the excited state is rather short lived then F becomes wide and the resolution for hyperfine spectroscopy (see section 2.3) becomes too limited. The same effect can be caused by unfortunate values of nuclear moments of the two states involved in the Mdssbauer transition. Finally, difficulties to produce the source activity may hinder a wider application of measurements with that particular isotope. Difficulties in source preparation and poor resolution are, for example, present in and have prevented Mdssbauer spectroscopic studies of compounds of this most interesting actinide. 

Several specific problems have been addressed using hyperfine spectroscopy on the [NiFe] hydrogenases ... 

PROBING ELECTRONIC STRUCTURE THROUGH HYPERFINE SPECTROSCOPY 3... 

A large variety of hyperfine spectroscopy methods exist that allow the detection of hyperfine and nuclear quadrupole interactions electron spin-echo envelope modulation (ESEEM), ENDOR, and ELDOR-detected NMR (electron-electron doubleresonance detected nuclear magnetic resonance) [13]. Although there are cases in which ESEEM and ENDOR perform equally well, ESEEM-like methods tend to be... 

In practice, the EPR spectroscopist will thus be using a variety of multifrequency cw-EPR and hyperfine spectroscopy techniques to determine the different spin Hamiltonian parameters. This has led to new insights in biological systems as well as in material sciences and it would be impossible to give an exhaustive account of all these applications. Here, we merely give a few examples to give the reader an idea... 

J.L. Hall Sub-Doppler spectroscopy methane hyperfine spectroscopy and the ultimate resolution limit, in Laser Spectroscopy II, ed. by S. Haroche, J.C. Pebay-Peyroula, T.W. Hansch, S.E. Harris, Lecture Notes Phys., Vol.43 (Springer, Berlin, Heidelberg 1975) p.l05... 

J.L. Hall "Sub-Doppler-Spectroscopy, Methane Hyperfine Spectroscopy and the Ultimate Resolution Limits", in Ref. 1.7, p. 105 ff... 

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