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In vitro regulation of CaCO 3 crystal polymorphism by the highly acidic molluscan shell protein Aspein
Author(s) -
Takeuchi Takeshi,
Sarashina Isao,
Iijima Minoru,
Endo Kazuyoshi
Publication year - 2008
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/j.febslet.2008.01.026
Subject(s) - calcite , aragonite , pinctada fucata , chemistry , nucleation , crystallography , in vitro , polymorphism (computer science) , biomineralization , calcium carbonate , biophysics , biochemistry , mineralogy , chemical engineering , biology , pearl , gene , pearl oyster , philosophy , theology , organic chemistry , genotype , engineering
Biominerals, especially molluscan shells, generally contain unusually acidic proteins. These proteins are believed to function in crystal nucleation and inhibition. We previously identified an unusually acidic protein Aspein from the pearl oyster Pinctada fucata . Here we show that Aspein can control the CaCO 3 polymorph (calcite/aragonite) in vitro . While aragonite is preferentially formed in Mg 2+ ‐rich solutions imitating the extrapallial fluids of marine molluscs, Aspein exclusively induced calcite precipitation. Our results suggest that Aspein is involved in the specific calcite formation in the prismatic layer. Experiments using truncated Aspein demonstrated that the aspartic acid rich domain is crucial for the calcite precipitation.