We have applied a bifunctional spin label and EPR spectroscopy to determine membrane protein structural topology in magnetically-aligned bicelles, using monomeric phospholamban (PLB) as a model system. Bicelles are a powerful tool for studying membrane proteins by NMR and EPR spectroscopies, where magnetic alignment yields topological constraints by resolving the anisotropic spectral properties...

While EPR allows for the characterization of protein structure and function due to its exquisite sensitivity to spin label dynamics, orientation, and distance, these measurements are often limited in sensitivity due to the use of labels that are attached via flexible monofunctional bonds, incurring additional disorder and nanosecond dynamics. In this chapter, we present methods for using a bifu...

Nucleoside C, which contains a rigid nitroxide spin label, is effectively reduced in DNA by sodium sulfide to the corresponding amine, yielding a fluorescent probe (Cf) that can report the identity of its base-pairing partner in duplex DNA.

Introduction: Pulsed continuous arterial spin labeling (PCASL) was developed to provide improved label and control efficiencies and reduced RF dose compared to multi-slice CASL with a double adiabatic inversion (DAI) control, thus allowing PCASL to be used at high fields (1, 2). However, PCASL is susceptible to label and control plane aliasing and other artifacts related to the design of its la...

E. coli incorporates increasing proportions of saturated and long-chain fatty acids into phospholipids as growth temperature is increased. It was found that this compositional variation results in the biosynthesis of phospholipids that have identical viscosities at the temperature of growth of the cells. This "homeoviscous adaptation" can also be observed in E. coli membrane preparations. Visco...

& R R = spin label incorporated in cu-chymotrypsin and trypsin (1). The spectral results also show the power of applying such a method to structural comparison of active sites of new proteases whose threedimensional structures are not yet known. We present here the detailed syntheses and purifications of these spin labels and some of the specific problems encountered in preparing the inhibited ...

The miscibility and phase behavior of hydrated binary mixtures of two N-acylethanolamines (NAEs), N-myristoylethanolamine (NMEA), and N-palmitoylethanolamine (NPEA), with the corresponding diacyl phosphatidylethanolamines (PEs), dimyristoylphosphatidylethanolamine (DMPE), and dipalmitoylphosphatidylethanolamine (DPPE), respectively, have been investigated by differential scanning calorimetry (D...

Spin-labeled derivatives of high density (HDL) and low density (LDL) lipoproteins from human serum were prepared with N-(1-oxyl-2,2,6,6-tetramethyl-4-piperidinyl)-maleimide. At the low ratios of spin label to protein employed, no changes in circular dichroism or immunochemical reactions were detected. The lipoprotein derivatives, labeled in their protein moieties, exhibited electron spin resona...

Displacement of spin-labeled drugs from drug-specific antibodies in human serum can be measured by use of electron spin resonance. This "spin immunoassay" has advantages of speed, simplicity, and small volume requirements over other standard techniques such as gas-liquid, liquid-liquid, or thin-layer chromatography. Unlike radioimmunoassay, there is no need to separate free and bound label and ...