title: A shielding topology stabilizes the early stage protein-mineral complexes of fetuin-A and calcium phosphate: a time-resolved small-angle X-ray study.
abstract: We report on the earliest stages of the formation of complexes of calcium phosphate in the presence of the serum protein alpha(2)-HS glycoprotein/fetuin-A termed calciprotein particles (CPPs). Time-resolved small-angle X-ray scattering (TR-SAXS) and stopped-flow analysis were used to monitor the growth of protein mineral particles nucleating from supersaturated salt solutions. It was found that fetuin-A did not influence the formation of mineral nuclei. However, fetuin-A did prevent the aggregation of nuclei and thus mineral precipitation. Hence, fetuin-A shielded spontaneously formed mineral nuclei, leading to stable calciprotein particles in the first stage of mineralization. Fetuin-A is therefore critically required during the earliest stages of the formation of protein-mineral complexes in order to prevent uncontrolled mineralization.
authors.affiliation: Physikalische Chemie I, University of Bayreuth, 95444 Bayreuth, Germany.
authors.forename: Christophe N
authors.initials: CN
authors.lastname: Rochette
authors.forename: Sabine
authors.initials: S
authors.lastname: Rosenfeldt
authors.forename: Alexander
authors.initials: A
authors.lastname: Heiss
authors.forename: Theyencheri
authors.initials: T
authors.lastname: Narayanan
authors.forename: Matthias
authors.initials: M
authors.lastname: Ballauff
authors.forename: Willi
authors.initials: W
authors.lastname: Jahnen-Dechent
mesh_terms: D000818:Animals; D002130:Calcium Phosphates / Q000378:metabolism*; D002417:Cattle; D008903:Minerals / Q000378:metabolism*; D011485:Protein Binding; D055550:Protein Stability; D053838:Scattering, Small Angle; D013997:Time Factors; D014961:X-Ray Diffraction; D000509:alpha-Fetoproteins / Q000737:chemistry / Q000378:metabolism*
chemical_list: D002130:Calcium Phosphates; D008903:Minerals; D000509:alpha-Fetoproteins; C020243:calcium phosphate