<i>In vitro</i> regulation of CaCO<sub>3</sub> crystal polymorphism by the highly acidic molluscan shell protein Aspein

Takeuchi, Takeshi; Sarashina, Isao; Iijima, Mayumi; Endo, Kazuhiko

doi:10.1016/j.febslet.2008.01.026

Cited by 107 publications

(88 citation statements)

References 28 publications

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“…To investigate the crystal precipitation process, the ionic composition of the extrapallial fluid of marine molluscs, with a high Mg 2ϩ content (50 mM) relative to Ca 2ϩ (10 mM) (62), must be taken into consideration. In solution, Mg 2ϩ is harmful to calcite precipitation; this is why aragonite crystals become dominant in Mg 2ϩ -rich solutions (23). Consequently, for an efficient process of calcitic prismatic layer calcification, some regulatory factors are required to override this spontaneous condition to form calcite.…”

Section: Discussionmentioning

confidence: 99%

“…Previous reports have revealed that these highly acidic proteins can decide the calcium carbonate polymorphism in vitro (2,12,21,22). One striking example is Aspein (12,23), which acts as a crystal nucleator to induce calcite precipitation using the mechanism of ionotropy, and it is therefore crucial for the formation of the prismatic layer. In contrast, basic matrix proteins exclusively associated with the prismatic layer have been far less studied.…”

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confidence: 99%

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Cloning and Characterization of Prisilkin-39, a Novel Matrix Protein Serving a Dual Role in the Prismatic Layer Formation from the Oyster Pinctada fucata

Kong

Yan

et al. 2009

Journal of Biological Chemistry

101

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Molluscs form their shells out of CaCO 3 and a matrix of biomacromolecules. Understanding the role of matrices may shed some light on the mechanism of biomineralization. Here, a 1401-bp full-length cDNA sequence encoding a novel matrix protein was cloned from the mantle of the bivalve oyster, Pinctada fucata. The deduced protein (Prisilkin-39), which has a molecular mass of 39.3 kDa and an isoelectric point of 8.83, was fully characterized, and its role in biomineralization was demonstrated using both in vivo and in vitro crystal growth assays. Prisilkin-39 is a highly repetitive protein with an unusual composition of Gly, Tyr, and Ser residues. Expression of Prisilkin-39 was localized to columnar epithelial cells of the mantle edge, corresponding to the calcitic prismatic layer formation. Immunostaining in situ and immunodetection in vitro revealed the presence of a characteristic pattern of Prisilkin-39 in the organic sheet and in sheaths around the prisms. Prisilkin-39 binds tightly with chitin, an insoluble polysaccharide that forms the highly structured framework of the shell. Antibody injection in vivo resulted in dramatic morphological deformities in the inner shell surface structure, where large amounts of CaCO 3 were deposited in an uncontrolled manner. Moreover, Prisilkin-39 strictly prohibited the precipitation of aragonite in vitro. Taken together, Prisilkin-39 is the first protein shown to have dual function, involved both in the chitinous framework building and in crystal growth regulation during the prismatic layer mineralization. These observations may extend our view on the rare group of basic matrices and their functions during elaboration of the molluscan shell.

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Section: Discussionmentioning

confidence: 99%

mentioning

confidence: 99%

Cloning and Characterization of Prisilkin-39, a Novel Matrix Protein Serving a Dual Role in the Prismatic Layer Formation from the Oyster Pinctada fucata

Kong

Yan

et al. 2009

Journal of Biological Chemistry

101

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“…Characteristic Raman bands for calcite and aragonite were assigned as described elsewhere. [6][7][8][9] Calcite and aragonite are two common polymorphs of CaCO3 observed as biominerals.…”

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confidence: 99%

“…Characteristic Raman bands for calcite and aragonite were assigned as described elsewhere. [6][7][8][9] Calcite and aragonite are two common polymorphs of CaCO3 observed as biominerals.Stony coral forms needle-like aragonite crystals, but soft coral forms only calcite crystals. The protein-induced chemical structure in calcified organisms is an important factor contributing to their growth, but until now no direct evidence has been reported.…”

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Analysis of Protein-induced Calcium Carbonate Crystals in Soft Coral by Near-Field IR Microspectroscopy

Rahman

Oomori

2009

ANAL. SCI.

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Infrared (IR) vibrational spectroscopy is a well-established tool in materials and life-science research. This technique can obtain information regarding fundamentally important microchemical properties. Although it is widely used to analyze microchemical properties, the identification of chemical structure using vibrational spectroscopy at infrared wavelengths has been problematic because of the diffraction limits of conventional infrared microscopy, which result in low spatial resolution. For example, the spatial resolution of infrared (IR) spectroscopy is approximately 10 mm, but that of newly developed near-field IR spectra (NFIR) is 1 mm, or less. Therefore, sub-micrometer to sub-nanometer scale chemical structure analysis is difficult to achieve by conventional IR. Specifically, scientists have been hampered by difficulty to separate protein-associated small chemical compounds from biomineralized organisms. We have overcome this limitation by applying a newly developed nearfield optical technique and near-field optical microscope through NFIR with high spatial resolution. The combination of nearfield microscopy and spectroscopy enables spectra to be obtained with subwavelength spatial resolution for visible light. However, the application of the near-field optical technique to the mid-IR region has only been reported for microscopy thus far.1 The primary reason for this limitation is lack of availability of high-intensity sources and detectors for the IR region.In the present study, this technique was used with a soft coral, Lobophytum crassum, as a model calcifying organism. Soft coral is an important and integral part of marine ecosystems. It has an important role in benthic-pelagic coupling processes as a source of food for demersal grazers and predators, as a host of highly diverse microbial biomass, and as a bioeroder. Soft coral contains small spicules of calcium carbonate, called "sclerites." Sclerites can strengthen the base of the soft coral, and are used by scientists to assist in the identification of soft coral species. Sclerites are the major mineralized structures present in these organisms. To address this importance, in vitro crystallization experiments were carried out in the presence of matrix proteins extracted from sclerites.A supersaturated solution of Ca(HCO3)2 was prepared by purging a stirred aqueous suspension of CaCO3 with carbon dioxide. 2 An aragonitic solution was obtained by adding 50 mM MgCl2 to supersaturated solution. Crystallization experiments were carried out with and without the addition of 700 mg of soluble proteins (extracted from sclerites) to the solution (500 ml). The solutions were then allowed to sit for one month without further manipulation. The protein concentration in the organic matrix was measured by method of Lowry et al. 3 using chicken ovalbumin (Kanto Chemical, Tokyo, Japan) as standard. The precipitate crystals were harvested from the solution after completion of each experiment, and each sample was stored for near-field probing analysis. An aperturele...

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“…in regulating and controlling CaCO 3 crystals growth and orientation, determining the shape, size and polymorph [24][25][26][27][28][29], maintaining the mechanical performances [18], even displaying enzymatic functions [30] and involving in cell signalling [31]. Currently, there is a great deal of work relating with the purification and characterization of proteins from mollusk shell [32][33][34][35][36][37][38].…”

Section: Yang Et Almentioning

confidence: 99%

Inter-prismatic matrix structure characterizationof mollusk shell and its effect on crystal formation

Yang¹,

Huang²,

Pan³

et al. 2010

Nano BioMed ENG

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Mollusk biomineralization is an elaborate process in which cells, organic macromolecules, and calcium carbonate crystals are actively involved.Macromolecules (mainly are proteins and polysaccharide) act as a key role in regulating and limiting the size, orientation, polymorph and texture of inorganic phase. In this work, we focused on the inter-prismatic matrix of mollusk shell combining scanning electron microscopy (SEM), X-ray diffraction (XRD) and transmission electron microscopy (TEM) analytical techniques with CaCO 3 recrystallization experiment to characterize its structure and effects on crystal formation. Our results show that the inter-prismatic matrix is not a sort of pure polymer, calcite nano-crystals are also located inside the inter-prismatic matrix. Interestingly, it seems that these nanocrystals have a preferred orientation, which means the inter-prismatic matrix do impose effect on the crystal formation. In vitro re-crystallization experiment using partially dissolved prismatic fragment as template indicates that the (104) faces of CaCO 3 micro-crystals are closely associated with the walls of inter-prismatic matrix. Furthermore, a possible growth mechanism of mollusk shell prismatic layer was proposed.Key Words: Biomineralization, Mollusk shell, Inter-prismatic matrix, Calcite, Dissolution Citation: D. Yang, et al. Inter-prismatic matrix structure characterization of mollusk shell and its effect on crystal formation. Nano Biomed. Eng.

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In vitro regulation of CaCO₃ crystal polymorphism by the highly acidic molluscan shell protein Aspein

Cited by 107 publications

References 28 publications

Cloning and Characterization of Prisilkin-39, a Novel Matrix Protein Serving a Dual Role in the Prismatic Layer Formation from the Oyster Pinctada fucata

Cloning and Characterization of Prisilkin-39, a Novel Matrix Protein Serving a Dual Role in the Prismatic Layer Formation from the Oyster Pinctada fucata

Analysis of Protein-induced Calcium Carbonate Crystals in Soft Coral by Near-Field IR Microspectroscopy

Inter-prismatic matrix structure characterizationof mollusk shell and its effect on crystal formation

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In vitro regulation of CaCO3 crystal polymorphism by the highly acidic molluscan shell protein Aspein

Cited by 107 publications

References 28 publications

Cloning and Characterization of Prisilkin-39, a Novel Matrix Protein Serving a Dual Role in the Prismatic Layer Formation from the Oyster Pinctada fucata

Cloning and Characterization of Prisilkin-39, a Novel Matrix Protein Serving a Dual Role in the Prismatic Layer Formation from the Oyster Pinctada fucata

Analysis of Protein-induced Calcium Carbonate Crystals in Soft Coral by Near-Field IR Microspectroscopy

Inter-prismatic matrix structure characterizationof mollusk shell and its effect on crystal formation

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In vitro regulation of CaCO₃ crystal polymorphism by the highly acidic molluscan shell protein Aspein