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Accelerated Calcium Phosphate Mineralization by Peptides with Adjacent Oppositely Charged Residues
journal contribution
posted on 2020-06-29, 09:29 authored by Mustafa Gungormus, Mahmut Sertac Ozdogan, Sinan Yasin Ertem, Fatih Tulumbaci, Halil Kara, Metin OrhanCalcium
phosphate mineralizing peptides are of special importance
for dental and orthopedic applications, such as caries remineralization
and improved osteointegration. Uncovering the mechanism of action
for such peptides is an ongoing challenge with the aim of a better
fundamental understanding of biomineralization processes and developing
optimized peptides for clinical use. It has recently been reported
that “adjacent oppositely charged residue” motifs are
found abundantly in cation binding, inorganic surface binding, or
biomineralization-related proteins and may play a key role in the
biomineralization events. Despite their medical importance, the role
of these motifs has not yet been investigated on calcium phosphate
mineral systems. To investigate this, we have designed peptides with
different structural properties and different numbers of adjacent
oppositely charged residues. We have evaluated their effects on in vitro calcium phosphate mineralization kinetics and mineral
properties. The kinetics of the mineralization increased proportionally
with an increasing number of adjacent oppositely charged residues.
Two peptides with relatively high structural stability and two adjacent
oppositely charged residues resulted in faster mineralization and
more crystalline mineral compared to a peptide with a higher structural
degree of freedom that contained only acidic residues. The fastest
mineralization and the highest mineral crystallinity were obtained
with a peptide containing the highest number of adjacent oppositely
charged residues and highest structural degree of freedom. Our findings
and observations from previously identified natural or designed peptides
indicate that, in addition to structural instability, adjacent oppositely
charged residues play a role in the cation binding, inorganic surface
binding, and biomineralization of peptides and require further investigation.
Lastly, the peptide identified in this study is an agent with potential
medical applications involving the treatment of mineralized tissues.