Membranes spin labeling

Subczynski, W. K., E. Markowska, W. I. Gruszecki, and J. Sielewiesiuk. 1992. Effects of polar carotenoids on dimyristoylphosphatidylcholine membranes Spin-label studies. Biochim. Biophys. Acta 1105 97-108. 

An extremely interesting class of problems concerns the behavior of guest molecules in host lipids, particularly when the host lipid system is in a condition where a solid fluid equilibrium exists in the plane of the membrane. Spin labels are ideal for the study of this problem. 

Ramakrishnan M, Jensen PH, Marsh D (2006) Association of alpha-synuclein and mutants with lipid membranes spin-label ESR and polarized IR. Biochemistry 45(10) 3386-3395. doi 10.1021/bi052344d... 

The heterogeneous structure of the swollen B. mori silk fibroin membrane was clarified from the complicated ESR spectra of the spin-labeled silk fibroin membranes. Spin-label ESR methods are useful for dynamic analysis of silk fibroin because of the inherent high sensitivity of ESR observation and the wide detectable range of the motion of the spin-labeled site, from 10 to lO " s. The hydroxy group of the Tyr side-chain is active and thus it can be labeled with nitroxide radical compounds as shown in Fig. 31. ... 

Ligeza A, Tikhonov AN, Hyde JS, Subczynski WK. 1998. Oxygen permeability of thylakoid membranes Electron paramagnetic resonance spin labeling study. Biochim Biophys Acta 1365 453. 

Schreier, S. Frezzatti, W. A., Jr. Araujo, R S. Chaimovich, H. Cuccovia, I. M., Effect of lipid membranes on the apparent pK of the local anesthetic tetracaine Spin label and titration studies, Biochim. Biophys. Acta 769, 231-237 (1984). 

A planar BLM cannot be investigated by means of the molecular spectroscopical methods because of the small amount of substance in an individual BLM. This disadvantage is removed for liposomes as they can form quite concentrated suspensions. For example, in the application of electron spin resonance (ESR) a spin-labelled phospholipid is incorporated into the liposome membrane this substance can be a phospholipid with, for example, a 2,2,6,6-tetramethylpiperidyl-A-oxide (TEMPO) group ... 

Strzalka, K. and W.I. Gruszecki. 1994. Effect of beta-carotene on structural and dynamic properties of model phosphatidylcholine membranes. I. An EPR spin label study. Biochim. Biophys. Acta 1194 138-142. 

EPR Spin-Labeling Demonstrates Membrane Properties Significant for Chemical... 

The membranes used in EPR measurements are usually multilamellar dispersions of lipids (mul-tilamellar liposomes) containing an investigated carotenoid and 0.5-1.0mol% of an appropriate lipid spin label (Figure 10.1). The total amount of lipids usually is 5-10 pmol per sample. 

In the membrane lipid alkyl chains of n-SASL and n-PC spin labels undergo rapid rotational motion about the long axis of the spin label and wobble within the confines of a cone imposed by the... 

We would like to point out that an order parameter indicates the static property of the lipid bilayer, whereas the rotational motion, the oxygen transport parameter (Section 4.1), and the chain bending (Section 4.4) characterize membrane dynamics (membrane fluidity) that report on rotational diffusion of alkyl chains, translational diffusion of oxygen molecules, and frequency of alkyl chain bending, respectively. The EPR spin-labeling approach also makes it possible to monitor another bulk property of lipid bilayer membranes, namely local membrane hydrophobicity. 

Here x from Equation 10.4 is changed to the two-membrane domain FOT and SLOT with the depth fixed (the same spin label is distributed between the FOT and SLOT domains). W(FOT) and W(SLOT) are oxygen transport parameters in each domain and represent the collision rate in samples equilibrated with air. Figure 10.9 illustrates the basis of the discrimination by oxygen transport (DOT) method, showing saturation-recovery EPR signals for 5-SASL in membranes... 

The hypothesis that polar carotenoids regulate membrane fluidity of prokaryotes (performing a function similar to cholesterol in eukaryotes) was postulated by Rohmer et al. (1979). Thus, the effects of polar carotenoids on membrane properties should be similar in many ways to the effects caused by cholesterol. These similarities were demonstrated using different EPR spin-labeling approaches in which the effects of dipolar, terminally dihydroxylated carotenoids such as lutein,... 

Recently, due to increased interest in membrane raft domains, extensive attention has been paid to the cholesterol-dependent liquid-ordered phase in the membrane (Subczynski and Kusumi 2003). The pulse EPR spin-labeling DOT method detected two coexisting phases in the DMPC/cholesterol membranes the liquid-ordered and the liquid-disordered domains above the phase-transition temperature (Subczynski et al. 2007b). However, using the same method for DMPC/lutein (zeaxanthin) membranes, only the liquid-ordered-like phase was detected above the phase-transition temperature (Widomska, Wisniewska, and Subczynski, unpublished data). No significant differences were found in the effects of lutein and zeaxanthin on the lateral organization of lipid bilayer membranes. We can conclude that lutein and zeaxanthin—macular xanthophylls that parallel cholesterol in its function as a regulator of both membrane fluidity and hydrophobicity—cannot parallel the ability of cholesterol to induce liquid-ordered-disordered phase separation. 

EPR SPIN-LABELING DEMONSTRATES MEMBRANE PROPERTIES SIGNIFICANT FOR CHEMICAL REACTIONS AND PHYSICAL PROCESSES INVOLVING CAROTENOIDS... 

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. 

Kusumi, A., W. K. Subczynski, and J. S. Hyde. 1982a. Effects of pH on ESR spectra of stearic acid spin labels in membranes Probing the membrane surface. Fed. Proc. 41 1394. 

Marsh, D. 1981. Electron spin resonance Spin labels. In Membrane Spectroscopy. Molecular Biology, Biochemistry, and Biophysics, ed. E. Grell, Vol. 31, pp. 51-142. Berlin, Germany Springer-Verlag. 

Subczynski, W. K. and A. Kusumi. 2003. Dynamics of raft molecules in the cell and artificial membranes Approaches by pulse EPR spin labeling and single molecule optical microscopy. Biochim. Biophys. Acta 1610 231-243. 

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