Abstract
Acid proteins capable of nucleating Ca2+ and displaying aggregation capacity play key roles in the formation of calcium carbonate biominerals. The helix-loop helix EF-hands are the most common Ca2+-binding motifs in proteins. Calcium is bound by the loop region. These motifs are found in many proteins that are regulated by calcium. Gad m 1, an Atlantic cod β-parvalbumin isoform, is a monomeric EF-hand protein that acts as a Ca2+ buffer in fish muscle; the neutral and acid apo-forms of this protein can form amyloids. Since Ca2+-nucleating proteins have a propensity to form extended β-strand structures, we wondered whether amyloid assemblies of an EF-hand protein were able to influence calcium carbonate crystallization in vitro. Here, we used the Gad m 1 chain as a model to generate monomeric and amyloid assemblies and to analyze their effect on calcite formation in vitro. We found that only amyloid assemblies alter calcite morphology.
Highlights
Calcium carbonate biominerals are the most abundant natural biocomposites; these biominerals are used for shell formation and for balancing systems [1,2]
We found that amyloid assemblies, but not monomers, perturbed calcite crystallization from the conventional rhombohedral habit to a sheaf-like morphology
Recent research showed that amyloid aggregates constitute basic scaffold for their functional exploitation in material science such as in the generation biominerals
Summary
Calcium carbonate biominerals are the most abundant natural biocomposites; these biominerals are used for shell formation and for balancing systems [1,2]. Acid proteins play major roles in the nucleation, growth and morphology of carbonate crystals by modulating Ca2+ condensation [3,4,5,6,7,8] These proteins share an oligomerization propensity involving extended β-strand structures, suggesting that amyloid protein assemblies with acidic regions could acquire biomineralization properties, such as the ability to modulate calcium carbonate crystallization [3,9,10,11]. The shape and topology of the aggregate can be modified by changing the sequence and the conditions used for their formation [14,15] Despite their variations in size and shape, all amyloids are characterized by structural repetitiveness and the resulting interactions [12]. The amyloid fold of the segment leads to the presence of novel binding sites absent in the monomer precursor, as in the case of Zn2+ and the assembled Ac-IHVHLQI-CONH2 peptide [18,19]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
