A pseudopotential has been introduced into NMR protein structure determination that effectively restrains molecular volume based on the observation that rigid, well-packed protein structures are approximately ellipsoidal. Allowing an ellipsoidal shape is more general than the single approximately spherical shape imposed by the radius of gyration pseudopotential introduced previously. We demonst...

Traditionally the dispersion of particles in polymeric materials has proven difficult and frequently results in phase separation and agglomeration. We show that thermodynamically stable dispersion of nanoparticles into a polymeric liquid is enhanced for systems where the radius of gyration of the linear polymer is greater than the radius of the nanoparticle. Dispersed nanoparticles swell the li...

A substantial separation of the centers of mass of the protein and RNA portions of the 50S ribosomal subunit has been achieved using neutron scattering. This separation reveals that the subunit has a protein-rich side, a finding which is inconsistent with many models proposed for the structure. By analyzing the variation of the radius of gyration of the subunit under conditions in which the con...

There are several important questions on the coupling between properties of the protein shape and the rate of protein folding. We have studied a series of structural descriptors intended for describing protein shapes (the radius of gyration, the radius of cross-section, and the coefficient of compactness) and their possible connection with folding behavior, either rates of folding or the emerge...

The conformational complexity of chain-like macromolecules such as proteins and other linear polymers is much larger than that of point-like atoms and molecules. Unlike particles, chains can bend, twist, and even become knotted. Thus chains might also display a much richer phase structure. Unfortunately, it is not very easy to characterize the phase of a long chain. Essentially, the only known ...

Flory Fox, Kurata-Stockmayer, Berry, Inagaki-Suzuki-Kurata, Stockmayer-Fixman and Ahmad-Baloch methods based on the excluded volume theory have been applied to poly(vinyl chloride)-cyclohexanone system to obtain Kq and the radius of gyration. A discussion on the reliability of these methods is given. The Stockmayer-Fixman and Ahmad-Baloch methods are found to be...

Previous work has shown that the predominant native form of the acetylcholine receptor from the electric tissue of Torpedo californica is a dimer of Mr = 500,000, cross-linked by a disulfide bond between the largest (delta) of the five chains (alpha 2 beta gamma delta) that comprise the monomer. Small-angle neutron scattering of purified receptor dimer in Triton X-100 solution containing 18% D2...

We use confocal fluorescence microscopy to study the conformation of single DNA molecules end-tethered to a solid substrate. The segment distribution rho(z) measured for chains with contour lengths 15.4 microm <or= L <or= 59.4 microm as a function of the distance from the substrate can be scaled onto a master curve depending only on the scaled distance z/R(g), in quantitative agreement with the...