title: Amelogenin nanoparticles in suspension: deviations from spherical shape and pH-dependent aggregation.
abstract: It is well-known that amelogenin self-assembles to form nanoparticles, usually referred to as amelogenin nanospheres, despite the fact that not much is known about their actual shape in solution. In the current paper, we combine SAXS and DLS to study the three-dimensional shape of the recombinant amelogenins rP172 and rM179. Our results show for the first time that amelogenins build oblate nanoparticles in suspension using experimental approaches that do not require the proteins to be in contact with a support material surface. The SAXS studies give evidence for the existence of isolated amelogenin nano-oblates with aspect ratios in the range of 0.45-0.5 at pH values higher than pH 7.2 and show an aggregation of these nano-oblates at lower pH values. The role of the observed oblate shape in the formation of chain-like structures at physiological conditions is discussed as a key factor in the biomineralization of dental enamel.
authors.affiliation: Department of Biomaterials, Max Planck Institute of Colloids and Interfaces, Potsdam, Germany. aichmayer@mpikg.mpg.de
authors.forename: Barbara
authors.initials: B
authors.lastname: Aichmayer
authors.forename: Felicitas B
authors.initials: FB
authors.lastname: Wiedemann-Bidlack
authors.forename: Christoph
authors.initials: C
authors.lastname: Gilow
authors.forename: James P
authors.initials: JP
authors.lastname: Simmer
authors.forename: Yasuo
authors.initials: Y
authors.lastname: Yamakoshi
authors.forename: Franziska
authors.initials: F
authors.lastname: Emmerling
authors.forename: Henry C
authors.initials: HC
authors.lastname: Margolis
authors.forename: Peter
authors.initials: P
authors.lastname: Fratzl
mesh_terms: D053523:Amelogenin / Q000032:analysis / Q000737:chemistry*; D000818:Animals; D006863:Hydrogen-Ion Concentration; D051379:Mice; D053758:Nanoparticles / Q000032:analysis / Q000737:chemistry*; D010316:Particle Size; D013499:Surface Properties; D013552:Swine; D014961:X-Ray Diffraction
chemical_list: D053523:Amelogenin