![]() Examples of proteins engaged in bones and teeth biomineralization are shown in Table 1.Īmong organic phase components, there are insoluble substances, which include structural macromolecules, creating a scaffold for the growing mineral. High content of IDPs’ carboxyl and phosphate acidic groups involved in biomineralization results in high calcium binding capabilities. The highly charged character, along with the low content of hydrophobic amino acid residues, results in strong electrostatic repulsion and the lack of a well-packed hydrophobic core. IDPs are dynamic, flexible, heterogeneous populations of molecules without a well-defined folded structure. They are usually highly acidic, undergo extensive posttranslational modifications, and frequently belong to the group of intrinsically disordered proteins (IDPs). Nucleation and crystal growth regulation are controlled by soluble, noncollagenous proteins. In human bones, collagen makes up to 20–30% wt. Scaffold for a growing mineral phase provides insoluble collagen. Among them, two major groups can be distinguished. Biomineralization involves protein-protein interactions and interactions between proteins and inorganic fraction. The key factors, which determine the size, shape, internal structure and properties of biominerals, are proteins, which control the nucleation and growth of the crystals. Moreover, having formed in vivo under well-controlled conditions, biomineral phases often have properties, such as shape, size, crystallinity, isotopic, and trace element compositions, quite unlike their inorganically formed counterparts. About 70% of bone tissue is made up of mineral structure, while the rest is water and organic substances. Stiffness of the tissue depends on the amount of inorganic components and organic phase. The mineral constituent gives tissues hardness and resistance to mechanical damage. In contrast to geological minerals, biominerals are composite materials comprised of both inorganic and bioorganic components. Due to strict control, biominerals differ from pure chemical minerals. īiomineralization is a multistep process, which requires using the structures of extracellular matrix vesicles, numerous enzymes and glycoproteins. In organisms, calcium orthophosphates occur mainly in the form of poorly crystallized nonstoichiometric sodium-, magnesium-, and carbonate-containing HA-so-called biological apatite. Among them, most important are amorphous calcium phosphate, octacalcium phosphate, calcium hydrogenphosphate dihydrate, and calcium-deficient apatite and hydroxyapatite (HA). Human hard tissues are formed of calcium orthophosphates. Understanding of molecular basis of biomineralization is essential to obtain new biomaterials. In vertebrates, hard tissues provide body support, take part in tearing food, protect organs, and are reservoirs of calcium and phosphate. Biominerals are organic-inorganic composites, which fulfill various biological functions. Biomineralization is a process of formation of an inorganic solid within the biological system. ![]()
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