Duplicated or Hybridized Peptide Functional Domains Promote Oral Homeostasis

Abstract

Proteins that have existed for millions of years frequently contain repeats of functional domains within their primary structure, thereby improving their functional capacity. In the evolutionary young statherin protein contained within the in vivo-acquired enamel pellicle (AEP), we identified a single functional domain (DR9) located within the protein N-terminal portion that exhibits a higher affinity for hydroxyapatite and more efficient protection against enamel demineralization compared to other native statherin peptides. Thus, we tested the hypothesis that multiplication of functional domains of naturally occurring pellicle peptides amplifies protection against enamel demineralization. In addition, a specific amino acid sequence from histatin 3 (RR-14) was introduced to the hybrid peptides for further testing. Enamel specimens were sectioned to 150-µm thickness and randomly grouped as follows: DR9, DR9-DR9, DR9-RR14, statherin, histatin 1, or distilled water (control). After submersion for 2 h at 37°C, the specimens were placed in 2 mL demineralization solution for 12 d at 37°C. Upon sample removal, the remaining solution was subjected to colorimetric assays to determine the amount of calcium and phosphate released from each specimen. DR9-DR9 amplified protection against enamel demineralization when compared to single DR9 or statherin. Notably, the hybrid peptide DR9-RR14 demonstrated relatively strong protection when the antimicrobial property of these peptides was tested against Candida albicans and Streptococcus mutans. DR9-RR14 was able to maintain 50% of the antifungal activity compared with RR14 for C. albicans and similar values of S. mutans killing activity. This study has pioneered the functional exploration of the natural peptide constituents of the AEP and their evolution-inspired engineered peptides. The knowledge obtained here may provide a basis for the development of stable (proteinase-resistant) synthetic peptides for therapeutic use against dental caries, dental erosion, and/or oral candidiasis.

Bio- and Nanotechnology as the Key for Clinical Application of Salivary Peptide Histatin: A Necessary Advance

“…By joining two fragments or two different peptides, the result can produce a new molecule that has a dual-effect or synergic effect. The hybrid peptide DR9-RR14 produced by Basiri et al joined the active fragment of histatin-3 with the active fragment of statherin, resulting in a peptide with the potential to prevent tooth demineralization and antimicrobial activity [115].…”

A review on saliva implication in caries development and consequences on primary canines and molars

“…[36] Th e salivary electrolytes and proteins are involved in the control of the oral microbiota and the protection of the dental enamel from dissolution. Each of the salivary glands secretes in variable amounts a wide range of molecules: Statherins favoring enamel remineralization, [37] amylases, cystatins known for their proteolytic activity, [38] PRPs, mucins, and sIgA. Other proteins are also found in saliva in smaller amounts: Antimicrobial and antifungal histatins, [39] an antimicrobial peptide, beta (ß)-defensin-1, [40] and proteases.…”

Modulation of Streptococcus mutans Adherence to Hydroxyapatite by Engineered Salivary Peptides

“…Moreover, salivary proteins known to exert antimicrobial functions such as cystatins, lysozyme, myeloperoxidase, and histatins were identified in the AEP [2], some of them conserving their biological activity when adsorbed onto dental surfaces [13]. Even though it is not known if histatins conserve their antimicrobial function upon adsorption, the antimicrobial activity of histatin 3 and its naturally derived 14-residue peptide known as RR14 against S. mutans was recently demonstrated [14].…”

“…The adaptation of salivary proteins in response to evolutionary pressure is reflected in the formation of functional complexes by certain salivary proteins once secreted into the oral cavity, protecting them against proteolysis, modulating their biological functions, and allowing their distribution throughout the oral cavity [5]. The natural existence of proteinaceous complexes displaying multiple functions served as the basis for the development of the engineered hybrid peptide DR9-RR14 [14][15][16], which has antibacterial [14] effects against S. mutans.…”