Halogenated Cholesterol Alters the Phase Behavior of Ternary Lipid Membranes.

Eukaryotic plasma membranes exhibit nanoscale lateral lipid heterogeneity, a feature that is thought to be central to their function. Studying these heterogeneities is challenging since few biophysical methods are capable of detecting domains at submicron length scales. We recently showed that cryogenic electron microscopy (cryo-EM) can directly image nanoscale liquid-liquid phase separation in extruded liposomes due to its ability to resolve the intrinsic thickness and electron density differences of ordered and disordered phases.

Rapid Analysis of DEER Signals Including Short Distances.

Double electron electron resonance (DEER) spectroscopy is an important technique to measure distance distributions () for studying protein structures and protein-protein interactions. DEER data analysis can at times become challenging due to the lack of a detailed analytical signal expression or numerical methods with rapid computation time. We have derived an analytical expression κ, which includes both the pseudo-secular dipolar coupling (PSDC) and the finite pulse effects, especially important for shorter distances.

A Stable Aluminum Tris(dithiolene) Triradical.

A stable aluminum tris(dithiolene) triradical () was experimentally realized through a low-temperature reaction of the sterically demanding lithium dithiolene radical () with aluminum iodide. Compound was characterized by single-crystal X-ray diffraction, UV-vis and EPR spectroscopy, SQUID magnetometry, and theoretical computations. The quartet ground state of triradical has been unambiguously confirmed by variable-temperature continuous wave EPR experiments and SQUID magnetometry.

A Simulation Independent Analysis of Single- and Multi-Component cw ESR Spectra.

The accurate analysis of continuous-wave electron spin resonance (cw ESR) spectra of biological or organic free-radicals and paramagnetic metal complexes is key to understanding their structure-function relationships and electrochemical properties. The current methods of analysis based on simulations often fail to extract the spectral information accurately. In addition, such analyses are highly sensitive to spectral resolution and artifacts, users' defined input parameters and spectral complexity.

Theory and Least Squares Fitting of CW ESR Saturation Spectra Using the MOMD Model.

CW saturation experiments are widely used in ESR studies of relaxation processes in proteins and lipids. We develop the theory of saturation in ESR spectra in terms of its close relation with that of 2D-ELDOR. Our treatment of saturation is then based on the microscopic order macroscopic disorder (MOMD) model and can be used to fit the full CW saturation spectrum, rather than fitting just the peak-peak amplitude as a function of microwave field as is commonly done.