Solution structure of human plasma fibronectin under different solvent conditions. Fluorescence energy transfer, circular dichroism and light-scattering studies.

摘要: Abstract Human plasma fibronectin is a high molecular weight (530,000), multi-domain, modular glycoprotein, consisting of two nearly identical subunits disulfide-bridge close to their C-terminal ends. Three sites that can be differentially labeled with fluorescent probes are present on each subunit, the transglutaminase-sensitive Gln3 residue and free sulfhydryl residues, Cys1201 Cys2196. These located, respectively, in N-terminal heparin/fibrin-binding domain, between central DNA cell-binding domains, just before fibrin-binding domain. To map relative spatial arrangement these steady-state lifetime fluorescence energy transfer techniques were employed. Our results show minimal intramolecular distances Gln3-Cys1201 Gln3-Cys2196 pairs 5·5(±0·6) nm 5·7(±0·7) nm, as measured by methods. Lifetime methods gave somewhat higher 8·1(±0·2) 7·6(±0·2) sites. The binding heparin or subjection ionic strength had only minor effect, while presence 50% (w/v) glycerol, an increase about 25% was observed. A similar effect induced surface Cytodex beads, event which previously shown instead markedly intersubunit Gln3-Gln3 Cys1201-Cys1201 pairs. solution structure further investigated elastic light-scattering circular dichroism measurements. By light-scattering, radius gyration found 15·3(±0·8) 30% contrast value 8·6(±0·3) under physiological conditions. Far near ultraviolet spectra showed changes secondary take place increasing glycerol content solvent up 34% (w/v). complement available information its transition from native compact conformation more expanded form content. In either situation, seems retain basic structural core, N-terminal, regions strongly interacts other. major role hydrophobic forces, stabilizing conformations conditions, therefore postulated. extended forms seen many electron micrographs explained disruption proposed core upon adsorption surfaces.