Biomaterial Database

The secondary structure of human plasma fibronectin: conformational changes induced by acidic pH and elevated temperatures; a circular dichroic study. 1988

E Osterlund

Department of Biochemistry, University of Helsinki, Finland.

The secondary structure of native human plasma fibronectin, based on circular dichroic spectra, has been estimated to contain 79% beta sheet and 21% beta turn structures (Osterlund, E., Eronen, I., Osterlund, K. and Vuento, M. (1985) Biochemistry 24, 2661-2667). In this work changes in the secondary structure of the protein molecule are followed as a function of different temperatures and pH values by using circular dichroic spectroscopy in far- and near-ultraviolet regions. Conformational changes are reversible when raising the temperature quickly to 55 degrees C, and then cooling slowly to 20 degrees C. A few percent of alpha-helix is apparent, when the temperature is raised to 58.5 degrees C, but only about 9% random coil is formed, when the temperature is raised up to 70 degrees C. The largest conformational change is taking place, when fibronectin samples are heated from 57 to 58.5 degrees C. According to this study more than 90% of the secondary structure of the fibronectin molecule is preserved throughout the whole temperature range studied from 20 to 70 degrees C, and this is a fact even at pH as low as 3.0, when samples are fresh and not denatured by preparative procedures.

UI	MeSH Term	Description	Entries
D011487	Protein Conformation	The characteristic 3-dimensional shape of a protein, including the secondary, supersecondary (motifs), tertiary (domains) and quaternary structure of the peptide chain. PROTEIN STRUCTURE, QUATERNARY describes the conformation assumed by multimeric proteins (aggregates of more than one polypeptide chain).	Conformation, Protein,Conformations, Protein,Protein Conformations
D002942	Circular Dichroism	A change from planar to elliptic polarization when an initially plane-polarized light wave traverses an optically active medium. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)	Circular Dichroism, Vibrational,Dichroism, Circular,Vibrational Circular Dichroism
D005353	Fibronectins	Glycoproteins found on the surfaces of cells, particularly in fibrillar structures. The proteins are lost or reduced when these cells undergo viral or chemical transformation. They are highly susceptible to proteolysis and are substrates for activated blood coagulation factor VIII. The forms present in plasma are called cold-insoluble globulins.	Cold-Insoluble Globulins,LETS Proteins,Fibronectin,Opsonic Glycoprotein,Opsonic alpha(2)SB Glycoprotein,alpha 2-Surface Binding Glycoprotein,Cold Insoluble Globulins,Globulins, Cold-Insoluble,Glycoprotein, Opsonic,Proteins, LETS,alpha 2 Surface Binding Glycoprotein
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D006863	Hydrogen-Ion Concentration	The normality of a solution with respect to HYDROGEN ions; H+. It is related to acidity measurements in most cases by pH	pH,Concentration, Hydrogen-Ion,Concentrations, Hydrogen-Ion,Hydrogen Ion Concentration,Hydrogen-Ion Concentrations
D013696	Temperature	The property of objects that determines the direction of heat flow when they are placed in direct thermal contact. The temperature is the energy of microscopic motions (vibrational and translational) of the particles of atoms.	Temperatures