Transformation of amorphous calcium carbonate nanoparticles into aragonite controlled by ACCBP

CrystEngComm ◽  
2016 ◽  
Vol 18 (12) ◽  
pp. 2125-2134 ◽  
Author(s):  
Jingtan Su ◽  
Fangjie Zhu ◽  
Guiyou Zhang ◽  
Hongzhong Wang ◽  
Liping Xie ◽  
...  
Keyword(s):  
Calcium Carbonate ◽  
Binding Protein ◽  
Pearl Oyster ◽  
Amorphous Calcium Carbonate ◽  
Polymorph Selection ◽  
The Matrix ◽  
Extrapallial Fluid

Polymorph switching of calcium carbonate controlled by amorphous calcium carbonate-binding protein, an extrapallial fluid (EPF) protein from the pearl oyster, is investigated. The polymorph selection in nacre or pearl growth may be controlled not only by the nucleating template on the matrix but also by the physicochemical effects of EPF proteins.

Structural characterization of amorphous calcium carbonate-binding protein: an insight into the mechanism of amorphous calcium carbonate formation

2013 ◽  
Vol 453 (2) ◽  
pp. 179-186 ◽  
Author(s):  
Jingtan Su ◽  
Xiao Liang ◽  
Qiang Zhou ◽  
Guiyou Zhang ◽  
Hongzhong Wang ◽  
...  
Keyword(s):  
Calcium Carbonate ◽  
Binding Sites ◽  
Binding Protein ◽  
Homology Modelling ◽  
Size Exclusion ◽  
Structural Basis ◽  
Amorphous Calcium Carbonate ◽  
Carbonate Formation

ACC (amorphous calcium carbonate) plays an important role in biomineralization process for its function as a precursor for calcium carbonate biominerals. However, it is unclear how biomacromolecules regulate the formation of ACC precursor in vivo. In the present study, we used biochemical experiments coupled with bioinformatics approaches to explore the mechanisms of ACC formation controlled by ACCBP (ACC-binding protein). Size-exclusion chromatography, chemical cross-linking experiments and negative staining electron microscopy reveal that ACCBP is a decamer composed of two adjacent pentamers. Sequence analyses and fluorescence quenching results indicate that ACCBP contains two Ca2+-binding sites. The results of in vitro crystallization experiments suggest that one Ca2+-binding site is critical for ACC formation and the other site affects the ACC induction efficiency. Homology modelling demonstrates that the Ca2+-binding sites of pentameric ACCBP are arranged in a 5-fold symmetry, which is the structural basis for ACC formation. To the best of our knowledge, this is the first report on the structural basis for protein-induced ACC formation and it will significantly improve our understanding of the amorphous precursor pathway.

Control of Polymorph Selection in Amorphous Calcium Carbonate Crystallization by Poly(Aspartic Acid): Two Different Mechanisms

Small ◽  
2017 ◽  
Vol 13 (21) ◽  
pp. 1603100 ◽  
Author(s):  
Zhaoyong Zou ◽  
Luca Bertinetti ◽  
Yael Politi ◽  
Peter Fratzl ◽  
Wouter J. E. M. Habraken
Keyword(s):  
Calcium Carbonate ◽  
Aspartic Acid ◽  
Amorphous Calcium Carbonate ◽  
Polymorph Selection

scholarly journals Transcriptional regulation of the matrix protein Shematrin-2 during shell formation in pearl oyster

2018 ◽  
Vol 293 (46) ◽  
pp. 17803-17816 ◽  
Author(s):  
Yan Chen ◽  
Jing Gao ◽  
Jun Xie ◽  
Jian Liang ◽  
Guilan Zheng ◽  
...  
Keyword(s):  
Transcriptional Regulation ◽  
Transcription Factors ◽  
Calcium Carbonate ◽  
Matrix Protein ◽  
Pearl Oyster ◽  
Pinctada Fucata ◽  
Functional Assay ◽  
Shell Formation ◽  
Molluscan Shell ◽  
The Matrix

The molluscan shell is a fascinating biomineral consisting of a highly organized calcium carbonate composite. Biomineralization is elaborately controlled and involves several macromolecules, especially matrix proteins, but little is known about the regulatory mechanisms. The matrix protein Shematrin-2, expression of which peaks in the mantle tissues and in the shell components of the pearl oyster Pinctada fucata, has been suggested to be a key participant in biomineralization. Here, we expressed and purified Shematrin-2 from P. fucata and explored its function and transcriptional regulation. An in vitro functional assay revealed that Shematrin-2 binds the calcite, aragonite, and chitin components of the shell, decreases the rate of calcium carbonate deposition, and changes the morphology of the deposited crystal in the calcite crystallization system. Furthermore, we cloned the Shematrin-2 gene promoter, and analysis of its sequence revealed putative binding sites for the transcription factors CCAAT enhancer–binding proteins (Pf-C/EBPs) and nuclear factor-Y (NF-Y). Using transient co-transfection and reporter gene assays, we found that cloned and recombinantly expressed Pf-C/EBP-A and Pf-C/EBP-B greatly and dose-dependently up-regulate the promoter activity of the Shematrin-2 gene. Importantly, Pf-C/EBP-A and Pf-C/EBP-B knockdowns decreased Shematrin-2 gene expression and induced changes in the inner-surface structures in prismatic layers that were similar to those of antibody-based Shematrin-2 inhibition. Altogether, our data reveal that the transcription factors Pf-C/EBP-A and Pf-C/EBP-B up-regulate the expression of the matrix protein Shematrin-2 during shell formation in P. fucata, improving our understanding of the transcriptional regulation of molluscan shell development at the molecular level.

scholarly journals Pure hydroxyapatite synthesis originating from amorphous calcium carbonate

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Michika Sawada ◽  
Kandi Sridhar ◽  
Yasuharu Kanda ◽  
Shinya Yamanaka
Keyword(s):  
Calcium Carbonate ◽  
Calcium Phosphate ◽  
Room Temperature ◽  
Molar Ratio ◽  
Final Phase ◽  
Amorphous Calcium Carbonate ◽  
Phosphate Compound ◽  
Synthesis Strategy ◽  
Phosphorylation Reaction ◽  
Subsequent Calcination

AbstractWe report a synthesis strategy for pure hydroxyapatite (HAp) using an amorphous calcium carbonate (ACC) colloid as the starting source. Room-temperature phosphorylation and subsequent calcination produce pure HAp via intermediate amorphous calcium phosphate (ACP). The pre-calcined sample undergoes a competitive transformation from ACC to ACP and crystalline calcium carbonate. The water content, ACC concentration, Ca/P molar ratio, and pH during the phosphorylation reaction play crucial roles in the final phase of the crystalline phosphate compound. Pure HAp is formed after ACP is transformed from ACC at a low concentration (1 wt%) of ACC colloid (1.71 < Ca/P < 1.88), whereas Ca/P = 1.51 leads to pure β-tricalcium phosphate. The ACP phases are precursors for calcium phosphate compounds and may determine the final crystalline phase.

scholarly journals On the Relation of Amorphous Calcium Carbonate and the Macromechanical Properties of Sea Urchin Spines

2020 ◽  
Vol 22 (4) ◽  
pp. 1900922 ◽  
Author(s):  
Christoph Lauer ◽  
Sebastian Haußmann ◽  
Patrick Schmidt ◽  
Carolin Fischer ◽  
Doreen Rapp ◽  
...  
Keyword(s):  
Calcium Carbonate ◽  
Sea Urchin ◽  
Amorphous Calcium Carbonate ◽  
Sea Urchin Spines

scholarly journals Screening of a Protein That Interacts with the Matrix Attachment Region-Binding Protein fromDunaliella salina

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
Rui Yang ◽  
Zhaoxi Li ◽  
Yan Lin ◽  
Baosheng Yang ◽  
Tianyun Wang
Keyword(s):  
Binding Protein ◽  
Matrix Attachment Region ◽  
Regulatory Function ◽  
Glutathione S Transferase ◽  
Reading Frame ◽  
Cis Acting ◽  
Binding Partner ◽  
The Matrix ◽  
Attachment Region ◽  
Regulated Functions

We isolated the matrix attachment region-binding protein (MBP) DMBP-1 fromDunaliella salinain our previous studies. MBPs are part of the cis-acting protein family cluster. The regulatory function possibly works through the interaction of the MBPs with each other. In the present study, DMBP-1 was used as the bait in screening theD. salinacDNA library for DMBP-1 interactors that could potentially mediate the DMBP-1-regulated functions. A novel MBP, namely, DMBP-2, was identified as a DMBP-1 binding partner. The cDNA of DMBP-1 was 823 bp long and contained a 573 bp open reading frame, which encoded a polypeptide of 191 amino acids. The interaction between DMBP-2 and DMBP-1 was further confirmed through glutathione S-transferase pull-down assays.

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