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 calculate the average hydrodynamic stress on fractal aggregates of spheres using Stokesian dynamics. We find that for fractal aggregates of force-free particles, the stress does not grow as the cube of the radius of gyration, but rather as the number of particles in the aggregate. This behavior is only found for random aggregates of force-free particles held together by hydrodynamic lubricat...

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...

We report microsecond timescale molecular dynamics simulation of the complex formed between Pt(II)-phenanthroline and the 16 N-terminal residues of the Aβ peptide that is implicated in the onset of Alzheimer's disease, along with equivalent simulations of the metal-free peptide. Simulations from a variety of starting points reach equilibrium within 100 ns, as judged by root mean square deviatio...

Small-angle X-ray scattering and nuclear magnetic resonance were used to investigate the structural change of calcium-bound calmodulin (Ca2+/CaM) in solution upon binding to its antagonist, N-(6-aminohexyl)-5-chloro-1-naphthalenesulfonamide (W-7). The radius of gyration was 17.4+/-0.3 A for Ca2+/CaM-W-7 with a molar ratio of 1:5 and 20.3+/-0.7 A for Ca2+/CaM. Comparison of the radius of gyratio...

We experimentally investigated the equilibrium conformation and dynamics of single DNA molecules in slitlike nanochannels. We measured the in-plane radius of gyration (R )), diffusivity (D), and longest relaxation time (τ) of λ-DNA (48.5 kbp) as functions of the slit height using fluorescence microscopy. Our results show that the in-plane radius of gyration increases monotonically with decreasi...

On-line two-angle (15 and 90) light scattering measurements with a gel permeation chromatograph for linear and branched polystyrene in tetrahydrofuran (a good solvent) and in trans-decalin (a theta solvent) were made and compared with data from a multi-angle light scattering detector and literature values. Theoretically, weight-average molecular weight and the radius of gyration Rg can be det...

We use new algorithms, based on the finite lattice method of series expansion, to extend the enumeration of self-avoiding walks and polygons on the triangular lattice to length 40 and 60, respectively. For self-avoiding walks to length 40 we also calculate series for the metric properties of mean-square end-to-end distance, mean-square radius of gyration and the mean-square distance of a monome...

We use new algorithms, based on the finite lattice method of series expansion, to extend the enumeration of self-avoiding walks and polygons on the triangular lattice to length 40 and 60, respectively. For self-avoiding walks to length 40 we also calculate series for the metric properties of mean-square end-to-end distance, mean-square radius of gyration and the mean-square distance of a monome...