Pulsed EPR Spectroscopy

In the previous chapters experiments have been discussed in which one frequency is applied to excite and detect an EPR transition. In multiple resonance experiments two or more radiation fields are used to induce different transitions simultaneously [19, 20, 21, 22 and 23], These experiments represent elaborations of standard CW and pulsed EPR spectroscopy, and are often carried out to complement conventional EPR studies, or to refine the infonnation which can in principle be obtained from them. 

T. Prisner, M. Rohrer and F. MacMillan, Pulsed EPR spectroscopy Biological applications, Annu. Rev. Phys. Chem., 2001, 52, 279. 

Books concerning specifically the topic of EPR and/or ENDOR of metalloproteins seem not to have been published in the period concerned. A book dealing with all aspects of pulse EPR spectroscopy has been presented.3... 

Narr, E., Godt, A., andjeschke, G. (2002). Selective measurements ofa nitroxide-nitroxide separation of 5 nm and a nitroxide-copper separation of 2.5 nm in a terpyridine-based copper(II) complex by pulse EPR spectroscopy. Angew. Chem. Int. Ed. Engl. 41, 3907-3910. 

Stich TA, Yeagle GJ, Service RF, Debus RJ, Britt RD. Ligation of Dl-His332 and Dl-Aspl70 to the manganese cluster of photosystem II from Synechocystis assessed by multifrequency pulse EPR spectroscopy. Biochemistry. 2011 50(34) 7390-404. 

Kabil O, Toaka S, LoBrutto R, Shoemaker R, and Banerjee R (2001) Pyridoxal phosphate binding sites are similar in human heme-dependent and yeast heme-independent cystathionine beta-synthases. Evidence from P NMR and pulsed EPR spectroscopy that heme and PLP cofactors are not proximal in the human enzyme. Journal of Biological Chemistry 276,19350-5. 

Bennati M, Grupp A, Mehring M and Bauerle P (1996a) Pulsed EPR spectroscopy of the photoexcited triplet states of thiophene oligomers in frozen solution. J Phys Chem 100 2849-2853... 

In pulsed EPR spectroscopy, the magnetization is detected through formation and readout of an electron spin echo. In contrast to cw EPR, which uses relatively weak microwave powers (slOO mW), pulsed EPR... 

Prisner T, Rohrer M, MacMillan F (2001) Pulsed EPR spectroscopy biological applications. Annu Rev Phys Chem 52 270-313... 

Sicoli G, Wachowius F, Bennati M, Hobartner C (2010) Probing secondary structures of spin-labeled RNA by pulsed EPR spectroscopy. Angew Chem Int Ed Engl 49(36) 6443-6447. doi 10.1002/anie.201000713... 

Lesion-induced DNA weak stmctural changes detected by pulsed EPR spectroscopy combined with site-directed spin labelling. Nucleic Acids Res 37(10) 3165-3176. doi 10.1093/nar/gkpl65... 

Electron Spin Echo Envelope Modulation (ESEEM) and pulse Electron Nuclear Double Resonance (ENDOR) experiments are considered to be two cornerstones of pulse EPR spectroscopy. These techniques are typically used to obtain the static spin Hamiltonian parameters of powders, frozen solutions, and single crystals. The development of new methods based on these two effects is mainly driven by the need for higher resolution, and therefore, a more accurate estimation of the magnetic parameters. In this chapter, we describe the inner workings of ESEEM and pulse ENDOR experiments as well as the latest developments aimed at resolution and sensitivity enhancement. The advantages and limitations of these techniques are demonstrated through examples found in the literature, with an emphasis on systems of biological relevance. 

Maly T, Grgic L, Zwicker K, Zickermann V, Brandt U, Prisner T. 2006. Cluster N1 of complex I from Yarrowia lipolytica studied by pulsed EPR spectroscopy. J Biol Inorg Chem 11 343-350. 

Siddigui MK, L5nihenovah S, de vties MJMP, Prisner TF, Ludwig B. 2004. Distance and orientation studies of the Cua fragment of c)hochrome c oxidase with different cytochrome c hy pulsed EPR spectroscopy. Biochim Biophys Acta Bioenerg 1658 154-154. 

Trandafir F, ter Heerdt P, Fittipaldi M, Vinck E, Dewilde S, Moens L, van Doorslaer S. 2007. Stud5dng high-spin ferric heme proteins using pulsed EPR spectroscopy analysis of the ferric form of the E7Q mutant of human neuroglohin. Appl Magn Reson 31 553-572... 

This report was followed by several studies that used pulsed EPR spectroscopy to determine the fete of chelated vanadyl complexes in the organs of chronically treated rats. Fukui et al. measured the 2- and 3-pulse ESEEM spectra of rat kidney, liver, and bone from animals treated with VOSO4 or VO(pic)2 [71]. Dikanov and coworkers used ESEEM and the two-dimensional ESEEM technique hyperfine sublevel correlation (HYSCORE) spectroscopy to examine in detail the coordina-... 

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