title: Determination of secondary structure of normal fibrin from human peripheral blood.
abstract: The secondary structure of human fibrin from normal donors and from bovine and suilline plasma was studied by Fourier transform ir spectroscopy and a quantitative analysis of its secondary structure was suggested. For this purpose, a previously experimented spectrum deconvolution procedure based on the use of the Conjugate Gradient Minimisation Algorithm with the addition of suitable constraints was applied to the analysis of conformation-sensitive amide bands. This procedure was applied to amide I and III analysis of bovine and suilline fibrin, obtained industrially, and to amide III analysis of human fibrin clots. The analysis of both amide I and III in the first case was useful in order to test the reliability of the method. We found bovine, suilline, and human fibrin to contain about 30% alpha-helix (amide I and III components at 1653 cm-1, and 1312 and 1284 cm-1, respectively), 40% beta-sheets (amide I and III components at 1625 and 1231 cm-1, respectively) and 30% turns (amide I and III components at 1696, 1680, 1675 cm-1, and 1249 cm-1, respectively). The precision of the quantitative determination depends on the amount of these structures in the protein. Particularly, the coefficient of variation is < 10% for percentage values of amide I and III components > 15 and 5%, respectively. The good agreement of our quantitative data, obtained separately by amide I and amide III analysis, and consistent with a previous fibrinogen (from commercial sources) study that reports only information about fibrin beta-sheet content obtained by factor analysis, leads us to believe that the amounts of secondary structures found (alpha-helix, beta-sheets, and turns) are accurate.
authors.affiliation: Istituto Di Chimica Analitica Strumentale, Icas, Pisa, Italy.
authors.forename: E
authors.initials: E
authors.lastname: Bramanti
authors.forename: E
authors.initials: E
authors.lastname: Benedetti
authors.forename: A
authors.initials: A
authors.lastname: Sagripanti
authors.forename: F
authors.initials: F
authors.lastname: Papineschi
authors.forename: E
authors.initials: E
authors.lastname: Benedetti
mesh_terms: D000465:Algorithms; D000818:Animals; D002417:Cattle; D005337:Fibrin / Q000737:chemistry*; D006801:Humans; D015394:Molecular Structure; D017433:Protein Structure, Secondary; D017550:Spectroscopy, Fourier Transform Infrared; D013552:Swine
chemical_list: D005337:Fibrin