title: Macromolecular recognition directs calcium ions to coccolith mineralization sites.
abstract: Many organisms form elaborate mineralized structures, constituted of highly organized arrangements of crystals and organic macromolecules. The localization of crystals within these structures is presumably determined by the interaction of nucleating macromolecules with the mineral phase. Here we show that, preceding nucleation, a specific interaction between soluble organic molecules and an organic backbone structure directs mineral components to specific sites. This strategy underlies the formation of coccoliths, which are highly ordered arrangements of calcite crystals produced by marine microalgae. On combining the insoluble organic coccolith scaffold with coccolith-associated soluble macromolecules in vitro, we found a massive accretion of calcium ions at the sites where the crystals form in vivo. The in vitro process exhibits profound similarities to the initial stages of coccolith biogenesis in vivo.
authors: Max-Planck Institute of Colloids and Interfaces, Potsdam-Golm 14476, Germany. Max-Planck Institute of Molecular Plant Physiology, Potsdam-Golm 14476, Germany.
authors: Assaf
authors: A
authors: Gal
authors: GeoForschungsZentrum Potsdam, Potsdam 14473, Germany.
authors: Richard
authors: R
authors: Wirth
authors: Max-Planck Institute of Molecular Plant Physiology, Potsdam-Golm 14476, Germany.
authors: Joachim
authors: J
authors: Kopka
authors: Max-Planck Institute of Colloids and Interfaces, Potsdam-Golm 14476, Germany.
authors: Peter
authors: P
authors: Fratzl
authors: Max-Planck Institute of Colloids and Interfaces, Potsdam-Golm 14476, Germany.
authors: Damien
authors: D
authors: Faivre
authors: Max-Planck Institute of Molecular Plant Physiology, Potsdam-Golm 14476, Germany. scheffel@mpimp-golm.mpg.de.
authors: André
authors: A
authors: Scheffel
mesh_terms: D002118:Calcium / Q000737:chemistry*; D002119:Calcium Carbonate / Q000737:chemistry*; D002413:Cations, Divalent / Q000737:chemistry; D003460:Crystallization; D058087:Haptophyta / Q000378:metabolism*; D046911:Macromolecular Substances / Q000737:chemistry*; D058086:Microalgae / Q000378:metabolism*; D008855:Microscopy, Electron, Scanning
chemical_list: D002413:Cations, Divalent; D046911:Macromolecular Substances; D002119:Calcium Carbonate; D002118:Calcium