title: Structural dynamics of a colloidal protein-mineral complex bestowing on calcium phosphate a high solubility in biological fluids.
abstract: The concentration of mineral solutes in mammalian blood is considerably higher than that predicted by their solubility product. The plasma protein fetuin-A inhibits calcium phosphate deposition by forming colloidal calciprotein particles (CPPs). In this article the authors present a detailed small angle neutron scattering study including contrast variation analysis providing detailed quantitative information on the three-dimensional topology of the CPPs and on their morphogenesis. In detail the authors found the following: (i) A two stage growth process showing spontaneously formed primary particles with a size of about 500 A diameter that subsequently transformed to 1000 A sized particles which were stable for at least 24 h. (ii) A particular shielding topology was observed for the second CPP state, namely, that a densely packed fetuin-A monolayer covers a mineral core and thereby prevents further crystal growth. (iii) Transmission electron microscopy analysis of in vitro synthesized second state CPPs revealed striking similarities to material retrieved from a human peritonitis patient. This latter finding underscores the importance of short- and long-term stabilizations of CPPs by fetuin-A to enable clearing of mineral debris in the body.
authors.affiliation: Institute for Biomedical Engineering, Biointerface Group, RWTH Aachen University, D-52074 Aachen, Germany. alexander.heiss@post.rwth-aachen.de
authors.forename: A
authors.initials: A
authors.lastname: Heiss
authors.forename: W
authors.initials: W
authors.lastname: Jahnen-Dechent
authors.forename: H
authors.initials: H
authors.lastname: Endo
authors.forename: D
authors.initials: D
authors.lastname: Schwahn