title: Solid-state NMR study reveals collagen I structural modifications of amino acid side chains upon fibrillogenesis.
abstract: In vivo, collagen I, the major structural protein in human body, is found assembled into fibrils. In the present work, we study a high concentrated collagen sample in its soluble, fibrillar, and denatured states using one and two dimensional {(1)H}-(13)C solid-state NMR spectroscopy. We interpret (13)C chemical shift variations in terms of dihedral angle conformation changes. Our data show that fibrillogenesis increases the side chain and backbone structural complexity. Nevertheless, only three to five rotameric equilibria are found for each amino acid residue, indicating a relatively low structural heterogeneity of collagen upon fibrillogenesis. Using side chain statistical data, we calculate equilibrium constants for a great number of amino acid residues. Moreover, based on a (13)C quantitative spectrum, we estimate the percentage of residues implicated in each equilibrium. Our data indicate that fibril formation greatly affects hydroxyproline and proline prolyl pucker ring conformation. Finally, we discuss the implication of these structural data and propose a model in which the attractive force of fibrillogenesis comes from a structural reorganization of 10 to 15% of the amino acids. These results allow us to further understand the self-assembling process and fibrillar structure of collagen.
authors: Laboratoire de Chimie de la Matière Condensée de Paris, UMR 7574 Université Pierre et Marie Curie (UPMC)/Centre National de La Recherche Scientifique (CNRS)/Collège de France, UPMC, 4 place Jussieu, 75005 Paris, France.
authors: Paulo
authors: P
authors: De Sa Peixoto
authors: Laboratoire de Chimie de la Matière Condensée de Paris, UMR 7574 Université Pierre et Marie Curie (UPMC)/Centre National de La Recherche Scientifique (CNRS)/Collège de France, UPMC, 4 place Jussieu, 75005 Paris, France.
authors: Guillaume
authors: G
authors: Laurent
authors: Laboratoire de Chimie de la Matière Condensée de Paris, UMR 7574 Université Pierre et Marie Curie (UPMC)/Centre National de La Recherche Scientifique (CNRS)/Collège de France, UPMC, 4 place Jussieu, 75005 Paris, France.
authors: Thierry
authors: T
authors: Azaïs
authors: Laboratoire de Chimie de la Matière Condensée de Paris, UMR 7574 Université Pierre et Marie Curie (UPMC)/Centre National de La Recherche Scientifique (CNRS)/Collège de France, UPMC, 4 place Jussieu, 75005 Paris, France. Electronic address: gmosser@snv.jussieu.fr.
authors: Gervaise
authors: G
authors: Mosser
mesh_terms: D000596:Amino Acids / Q000737:chemistry; D024042:Collagen Type I / Q000737:chemistry*; D005109:Extracellular Matrix / Q000378:metabolism; D006801:Humans; D006863:Hydrogen-Ion Concentration; D006909:Hydroxyproline / Q000737:chemistry; D007098:Imino Acids / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D011392:Proline / Q000737:chemistry; D011487:Protein Conformation; D013696:Temperature
chemical_list: D000596:Amino Acids; D024042:Collagen Type I; D007098:Imino Acids; D011392:Proline; D006909:Hydroxyproline