Physical Chemistry of Macromolecules

Abstract

not Available.

Automated measurement of the static light scattering of macromolecular solutions over a broad range of concentrations

“…It is shown that the concentration dependence of each may be accounted for quantitatively over a wide concentration range by a simple model, according to which each protein molecule interacts with other protein molecules only via short-ranged repulsive interactions that may be approximated as hard particle interactions, and does not selfassociate to any significant extent over the concentration range examined. Molecular weights obtained for all three proteins agree well with literature values [4,18]. 2 We note that v eff is defined equal to the specific volume of a hard spherical particle whose interparticle interactions best mimic that of the actual protein under a particular set of experimental conditions.…”

“…The concentration dependence of the logarithm of the activity coefficient is obtained by modeling the protein molecule as an effective hard spherical particle [7]: (4) where φ denotes the fraction of volume occupied by protein, given by (5) and v eff is the specific volume of the effective hard spherical particle 2 . The infinite power series indicated in equation (4) is truncated after five terms since test calculations indicated convergence over the measured range of concentration.…”

“…Conventional analysis of the concentration dependence of colligative properties of protein solution -osmotic pressure, sedimentation equilibrium and static light scattering -have been limited to first-order deviations from thermodynamic ideality, or so called second virial coefficient corrections [4]. However, such corrections cannot account quantitatively for the behavior of solutions at concentrations exceeding ca 50 g/L [5,6].…”

Conformational changes of the H+‐ATPase from Escherichia coli upon nucleotide binding detected by single molecule fluorescence

“…At constant temperature and viscosity, the frictional coe¤cient, f, depends on the radius and the shape of the molecule [17]. We therefore conclude that binding of nucleotides (either ATP or AMPPNP) leads to a large conformational change in the F I part of the enzyme.…”

Efficient solution technique for solving the Poisson–Boltzmann equation

“…7 Solutions to simple problems with spherical, cylindrical, or planar symmetry are available for the linearized PB equation. 8,9 A closedform formula for the solution of nonlinear PB does not seem to be possible except for the planar case 10 and the infinite cylindrical symmetric case, where only counterions exist in the solution. 11 In attempting to use numerical methods to solve the PB equation with complicated molecular geometries and charge distributions, a number of challenges present themselves.…”