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Calcium-Induced Molecular Rearrangement of Peptide Folds Enables Biomineralization of Vaterite Calcium Carbonate

Lu, Hao, Lutz, Helmut, Roeters, Steven J., Hood, Matthew A., Schäfer, Arne, Muñoz-Espí, Rafael, Berger, Rüdiger, Bonn, Mischa, Weidner, Tobias
Journal of the American Chemical Society 2018 v.140 no.8 pp. 2793-2796
aragonite, biomineralization, calcite, calcium, calcium carbonate, glutamic acid, ions, leucine, molecular dynamics, nanosheets, peptides, proteins, simulation models, vaterite
Proteins can control mineralization of CaCO₃ by selectively triggering the growth of calcite, aragonite or vaterite phases. The templating of CaCO₃ by proteins must occur predominantly at the protein/CaCO₃ interface, yet molecular-level insights into the interface during active mineralization have been lacking. Here, we investigate the role of peptide folding and structural flexibility on the mineralization of CaCO₃. We study two amphiphilic peptides based on glutamic acid and leucine with β-sheet and α-helical structures. Though both sequences lead to vaterite structures, the β-sheets yield free-standing vaterite nanosheet with superior stability and purity. Surface-spectroscopy and molecular dynamics simulations reveal that reciprocal structuring of calcium ions and peptides lead to the effective synthesis of vaterite by mimicry of the (001) crystal plane.