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The concentration dependence of the structure of fibrin gels, formed following fibrinogen activation by thrombin at a constant molar ratio, was investigated by means of elastic light scattering techniques. The scattered intensity distributions were measured in absolute units over a wave-vector range q of about three decades ( approximately 3x10(2)-3x10(5)(More)
The interpretation of solution hydrodynamic data in terms of macromolecular structural parameters is not a straightforward task. Over the years, several approaches have been developed to cope with this problem, the most widely used being bead modeling in various flavors. We report here the implementation of the SOMO (SOlution MOdeller; Rai et al. in(More)
This study tested the hypothesis that high-affinity binding of macromolecular ligands to the alphaIIbbeta3 integrin is tightly coupled to binding-site remodeling, an induced-fit process that shifts a conformational equilibrium from a resting toward an open receptor. Interactions between alphaIIbbeta3 and two model ligands-echistatin, a 6-kDa recombinant(More)
UltraScan Solution Modeler (US-SOMO) processes atomic and lower-resolution bead model representations of biological and other macromolecules to compute various hydrodynamic parameters, such as the sedimentation and diffusion coefficients, relaxation times and intrinsic viscosity, and small angle scattering curves, that contribute to our understanding of(More)
Reduced numbers of frictional/scattering centers are essential for tractable hydrodynamic and small-angle scattering data modeling. We present a method for generating medium-resolution models from the atomic coordinates of proteins, basically by using two nonoverlapping spheres of differing radii per residue. The computed rigid-body hydrodynamic parameters(More)
Fibronectin has been purified to apparent homogeneity according to measurements of molecular weight and diffusion constant from light scattering and sedimentation in the analytical ultracentrifuge. This gives two estimates of molecular weight close to 500,000. (The difference with the gel electrophoretic value of 440,000 may indicate the presence of some(More)
The alpha IIb beta 3 platelet integrin is the prototypical member of a widely distributed class of transmembrane receptors formed by the noncovalent association of alpha and beta subunits. Electron microscopic (EM) images of the alpha IIb beta 3 complex show an asymmetric particle with a globular domain from which two extended regions protrude to contact(More)
Many biological supramolecular structures are formed by polymerization of macromolecular monomers. Light scattering techniques can provide structural information from such systems, if suitable procedures are used to collect the data and then to extract the relevant parameters. We present an experimental set-up in which a commercial multiangle laser light(More)
Although most time-of-flight (TOF) mass spectrometers come equipped with vacuum matrix-assisted laser desorption/ionization (MALDI) sources, the atmospheric pressure MALDI (API-MALDI) source is an attractive option because of its ability to be coupled to a wide range of analyzers. This article describes the use of an API-MALDI source coupled to a TOF mass(More)
The average pore size ξ0 of filamentous networks assembled from biological macromolecules is one of the most important physical parameters affecting their biological functions. Modern optical methods, such as confocal microscopy, can noninvasively image such networks, but extracting a quantitative estimate of ξ0 is a nontrivial task. We present here a fast(More)