Designed peptides for biomineral polymorph recognition: a case study for calcium carbonate

Area of Science:

• Biomineralization
• Materials Science
• Peptide Engineering

Background:

• Peptides control inorganic and soft material assembly through substrate recognition and self-assembly.
• Understanding peptide interactions with mineral polymorphs is crucial for materials science and biomineralization.
• Calcium carbonate exhibits diverse crystalline anhydrous polymorphs, including vaterite, aragonite, and calcite.

Purpose of the Study:

• To engineer a heptapeptide capable of differentiating between calcium carbonate polymorphs.
• To investigate the specific affinity of the engineered peptide for vaterite over aragonite.
• To demonstrate the peptide's ability to direct calcium carbonate crystallization towards a specific polymorph.

Main Methods:

• Design and engineering of a heptapeptide containing arginine and proline residues.
• Fluorescence microscopy using biotinylated peptides to assess vaterite vs. aragonite affinity.
• Crystallization experiments in the presence of the engineered peptide and its mutant.

Main Results:

• The engineered heptapeptide demonstrated selective affinity for vaterite over aragonite.
• Crystallization experiments with the vaterite-affine peptide exclusively produced vaterite.
• A mutant peptide, with proline replaced by glycine, exclusively induced calcite formation.

Conclusions:

• Engineered peptides can precisely control the selective crystallization of calcium carbonate polymorphs.
• This peptide-based approach offers a novel strategy for directing mineralization processes.
• The findings have implications for materials synthesis, biomimicry, and understanding biomineralization.