Spin-label technique

Ashikawa, I., J.-J. Yin, W. K. Subczynski, T. Kouyama, J. S. Hyde, and A. Kusumi. 1994. Molecular organization and dynamics in bacteriorhodopsin-rich reconstituted membranes Discrimination of lipid environments by the oxygen transport parameter using a pulse ESR spin-labeling technique. Biochemistry 33 4947 1952. 

Subczynski, W. K. and J. S. Hyde. 1984. Diffusion of oxygen in water and hydrocarbons using an electron spin resonance spin-label technique. Biophys. J. 45 743-748. 

The stability of nitroxides will be well known to readers acquainted with the spin-labelling technique (Berliner, 1976), but it must be recognized that nitroxides employed as spin labels or spin probes are almost invariably di-t-alkyl nitroxides. Diaryl and many aryl t-alkyl nitroxides are also sufficiently persistent to be isolated, and it has recently been shown that several acyl t-alkyl nitroxides can also be obtained pure (Perkins and Ward, 1973 Alewood et al., 1978). However, other nitroxides are less persistent. Monosubstituted nitroxides, RN(H)Q-, rapidly disproportionate to nitroso-... 

The above data show that the spin labelling technique indeed allows one to control the random character and the uniformity of the spatial distribution of the additives in vitreous matrices. The criterion of random character and uniformity of distribution is the linear dependence of the EPR line width on the concentration of paramagnetic additives and the coincidence of the experimentally measured coefficients A in eqn. (2) with the theoretical value of A for such distribution. 

Macosko, J. C., et al. (1999). A novel 5 displacement spin-labeling technique for electron paramagnetic resonance spectroscopy ofRNA. RNA 5, 1158-1166. 

To this end, the spin labeling technique was used to probe the active site structure of LADH in various solvent systems. The spin label, SL-1, alkylated cysteine 46 (12), an amino acid in the active site of LADH that normally serves as a ligand to the catalytic zinc ion. LADH is a dimer, and each monomeric subunit contains one firmly-bound catalytic zinc ion. The position of enzyme-bound SL-1 was estimated by the spin label-spin probe technique (14.15). Cobalt (II) was employed as the spin probe, and the catalytic zinc in the enzyme s active site was replaced by Co + according to the procedure of Sytkowski and Vallee (16). The EPR spectrum of enzyme-bound SL-1 was then measured before and after replacement of the active-site zinc by cobalt from the decrease in spectral amplitude the average nitroxide-metal distance was determined to be 4.8 1.5 A (17). 

T he use of spin-label probes to investigate cell membrane structure and function clearly demonstrates the fluidity of membrane lipid structures (1,2,3,4) however, a spin-label probe sees only its immediate environment. Predictions (5, 6, 7, 8) and data (9, 10, 11, 12) show that the introduction, for example, of a substituted oxazolidine ring as part of a typical amphiphatic lipid molecule can also significantly perturb a normal lipid environment. Consequently, some quantitative observations that used spin-label techniques need revision while others may be reduced to the level of qualitative predictions. 

We have been searching for experimental methods that can measure surface viscosities as low as 10 10 g/sec or measure the collisional dynamics that should correspond to the Mann-Cooper model. To qualify, the experimental method must respond to dilute monolayers having densities less than 1014 mojecules/cm2. From our experience with the ESR spin label technique for measuring bulk viscosity effects in ultrathin films (8),... 

We gratefully acknowledge conversations with L. H. Piette and his encouragement and help in working out this application of the spin label technique. We are most grateful for conversations with P. Devaux and J. C. Lang about exchange effects. 

The spin label technique appeared to be very fruitful recently in research ofmembrane-carotenoids interaction. The shape of a spin probe ESR spectrum is sensitive to the rate of its molecular motion being directly dependent on the membrane fluidity determined by the rate of lipid molecular motion. Thus, the analysis of ESR spectra of spin labels doped into pigmented membranes would provide information on the carotenoid effect on particular regions of lipid bilayers, dependent on the type of probes applied, penetrating different membrane portions. Tfiis technique was applied to study an effect of xanthophylls and j8-carotene on fluidity of lipid membranes formed with several synthetic and nonsaturated phosphatidylcholines (Subczynski et al, 1991,1992,1993 StrzalkaandGruszecki, 1991, Yin and Subczynski, 1996, Wisniewska and... 

It is not practical to cover every topic in this review in which radiation chemical techniques have contributed to the understanding of catalyst function or catalytic reactions. With this introduction as a cursory guide to relevant topics, we move on to a discussion of the radiolytic spin labeling technique for analyzing products of catalytic reactions in zeolites, which has been the main thrust of experiments directed at fundamental aspects of catalysis in our laboratory. 

It sounds simple, but as mass spectroscopists know, ionization as an analysis technique creates very reactive species. It is not enough to be able to detect ions one must also have knowledge of how the ions react. Fortunately, many radical cations are quite stable in selected zeolites at low temperature. For example, the excellent stability of radical cations of simple aromatic hydrocarbons and olefins in MFI zeolites has contributed to the successful application of the radiolytic spin labeling technique to catalytic processes of considerable importance to the fuels and petrochemical industries -hydrocarbon transformations in zeolite ZSM5. ... 

The study of proteins adsorption on MNPs was performed using ESR-spectroscopy of spin labels. The stable nitroxide radical used as spin label is presented in Fig. 3. Spin labels technique allows studying adsorption of macromolecules on nano-sized magnetic particles in dispersion without complicated separation processes of solution components [14]. The principle of quantitative evaluation of adsorption is the following. Influence of local fields of MNPs on spectra of radicals in solution depends on the... 

Bychkova, A. V. Sorokina, O. N. Kovarski, A. L. Shapiro, A. B. Rosenfeld, M. A. The Investigation of Polyethyleneimine Adsorption on Magnetite Nanoparticles by Spin Labels Technique. Nanosci. Nanotechnol. Lett. (ESR in Small Systems), 2011,3, 591-593. 

The results of our earlier investigation using spin-labelling technique to understand the structural aspects involved in the various emulsions, support the theory that water-external macroemulsions exist below optimal salinities and oil-external types exist beyond optimal salinity. In addition it was found that microemulsions coexisted with macroemulsions and were of the same type in the sonicated emulsions. These findings are further complemented by electrical conductance and bulk viscosity data. 

Jost, P.C. and Griffith, O.H., The Spin-Labeling Technique in Methods in Enzymology, Vol. XLIX, Academic Press, London, 1978. 

Investigation of local dynamics in some polymer systems using the ESR spin-label technique at various stages of development has been reviewed. The review shows that interpretation of experimental ESR data, based on the currently available theoretical models, can provide both data complementary to some other experimental techniques and data that clarify some newly observed effects. 

Saturation Transfer Spectroscopy of Spin-Labels Techniques and Interpretation of Spectra... 

Introduction Reflections on the Beginning of the Spin Labeling Technique... 

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