Dental enamel forms through a protein-controlled mineralization and enzymatic degradation process with a nanoscale precision that new engineering technologies may be able to mimic. Recombinant full-length human amelogenin (rH174) and a matrix-metalloprotease (MMP-20) were used in a pH-stat titration system that enabled a continuous supply of calcium and phosphate ions over several days, mimicking the initial stages of matrix processing and crystallization in enamel in vitro. Effects on the self-assembly and crystal growth from a saturated aqueous solution containing 0.4 mg/mL rH174 and MMP-20 with the weight ratio of 1:1000 with respect to rH174 were investigated. A transition from nanospheres to fibrous amelogenin assemblies was facilitated under conditions that involved interaction between rH174 and its proteolytic cleavage products. Despite continuous titration, the levels of calcium exhibited a consistent trend of decreasing, thereby indicating a possible role in protein self-assembly. This study suggests that mimicking enamel formation in vitro requires the synergy between the aspects of matrix self-assembly, proteolysis, and crystallization.
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P.R. Garant: Oral Cells and Tissues Quintessence Carol Stream, IL 2003
J.D. Bartlett, O.H. Ryu, J. Xue, J.P. Simmer, H.C. Margolis: Enamelysin mRNA displays a developmentally defined pattern of expression and encodes a protein which degrades amelogenin. Connect. Tissue Res. 39, 405 1998
J. Moradian-Oldak, C. Du, G. Falini: On the formation of amelogenin microribbons. Eur. J. Oral Sci. 114, (Suppl. 1) 289 2006
C. Du, G. Falini, S. Fermani, C. Abbott, J. Moradian-Oldak: Supramolecular assembly of amelogenin nanospheres into birefringent microribbons. Science 307, 1450 2005
F.B. Wiedemann-Bidlack, E. Beniash, Y. Yamakoshi, J.P. Simmer, H.C. Margolis: pH triggered self-assembly of native and recombinant amelogenins under physiological pH and temperature in vitro. J. Struct. Biol. 160, 57 2007
J.D. Bartlett, J.P. Simmer: Proteinases in developing enamel. Crit. Rev. Oral Biol. Med. 10(4), 425 1999
J.D. Bartlett, Z. Skobe, D.H. Lee, J.T. Wright, Y. Li, A.B. Kulkarni, C.W. Gibson: A developmental comparison of matrix metalloproteinase-20 and amelogenin null mouse enamel. Eur. J. Oral Sci. 114, (Suppl. 1) 18 2006
J.J. Caterina, Z. Skobe, J. Shi, Y. Dang, J.P. Simmer, H. Birkedal-Hansen, J.D. Bartlett: Enamelysin (MMP-20) deficient mice display an amelogenesis imperfecta phenotype. J. Biol. Chem. 277(51), 49598 2002
W. Li, C. Gao, Y. Yan, P.K. DenBesten: X-linked amelogenesis imperfecta may result from decreased formation of tyrosine rich amelogenin peptide (TRAP). Arch. Oral Biol. 48, 177 2003
M.B. Tomson, G.H. Nancollas: Mineralization kinetics: A constant composition approach. Science 200, 1059 1978
S. Habelitz, P.K. DenBesten, S.J. Marshall, G.W. Marshall, W. Li: Amelogenin control over apatite crystal growth is affected by the pH and degree of ionic saturation. Orthod. Craniofac. Res. 8, 232 2005
H. McDowell, T.M. Gregory, W.E. Brown: Solubility of Ca5(PO4) 3OH in the system Ca(OH)2–H3PO4–H2O at 5, 15, 25 and 37.5 °C. J. Res. Natl. Bur. Stand. 81A, 273 1977
M.J. Larsen: Ion Products and Solubility of Calcium Phosphates Royal Dental College Denmark 2001
P. Koutsoukas, Z. Amjad, M.B. Tomson, G.H. Nancollas: Crystallization of calcium phosphates. A constant composition study. J. Am. Chem. Soc. 102, 1553 1980
J.D. Featherstone, I. Mayer, F.C. Driessens, R.M. Verbeeck, H.J. Heijligers: Synthetic apatites containing Na, Mg, and CO3 and their comparison with tooth enamel mineral. Calcif. Tissue Int. 35, 169 1983
J. Moradian-Oldak: Amelogenins: Assembly, processing and control of crystal morphology. Matrix Biol. 20, 293 2001
E. Beniash, J.P. Simmer, H.C. Margolis: The effect of recombinant mouse amelogenins on the formation and organization of hydroxyapatite crystals in vitro. J. Struct. Biol. 149(2), 182 2005
T. Hoche, C. Moisescu, I. Avramov, C. Russel, W.D. Heerdegen, C. Jager: Microstructure of SiO2–Al2O3–CaO–P2O5–Na2O–K2O–F glass ceramics. 2. Time dependence of apatite crystal growth. Chem. Mater. 13, 1320 2001
B. Bochicchio, A.M. Tamburro: Polyproline II structure in proteins: Identification by chiroptical spectroscopies, stability, and functions. Chirality 14, 782 2002
A. Rath, A.R. Davidson, C.M. Deber: The structure of “unstructured” regions in peptides and proteins: Role of the polyproline II helix in protein folding and recognition. Biopolymers 80, 179 2005
T.Q. Le, M. Gochin, J.D.B. Featherstone, W. Li, P.K. DenBesten: Comparative calcium binding of leucine-rich amelogenin peptide and full-length amelogenin. Eur. J. Oral Sci. 114, (Suppl. 1) 320 2006
G.K. Hunter, H.A. Curtis, M.D. Grynpas, J.P. Simmer, A.G. Fincham: Effects of recombinant amelogenin on hydroxyapatite formation in vitro. Calcif. Tissue Int. 65, 226 1999
L. Wang, X. Guan, H. Yin, J. Moradian-Oldak, G.H. Nancollas: Mimicking the self-organized microstructure of tooth enamel. J. Phys. Chem. C 112(15), 5892 2008
L. Wang, X. Guan, C. Du, J. Moradian-Oldak, G.H. Nancollas: Amelogenin promotes the formation of elongated apatite microstructures in a controlled crystallization system. J. Phys. Chem. C 111(17), 6398 2007
B.J. Tarasevich, C.J. Howard, J.L. Larson, M.L. Snead, J.P. Simmer, M. Paine, W.J. Shaw: The nucleation and growth of calcium phosphate by amelogenin. J. Cryst. Growth 304(2), 407 2007
V. Uskoković: Isn’t self-assembly a misnomer? Multi-disciplinary arguments in favor of Co-assembly. Adv. Colloid Interface Sci. 141(1–2), 37 2008
H. Cölfen, S. Mann: Higher-order organization by mesoscale self-assembly and transformation of hybrid nanostructures. Angew. Chem. Int. Ed. Engl. 42, 2350 2003
R.W. Fearnhead: The electron microscopy of amelogenesis in the rat. J. Dent. Res. 39, 1104 1960
J.E. Eastoe: The amino acid composition of proteins from the oral tissues. Arch. Oral Biol. 52, 633 1963
H.C. Margolis, E. Beniash, C.E. Fowler: Role of macromolecular assembly of enamel matrix proteins in enamel formation. J. Dent. Res. 85(9), 775 2006
M. Tourbez, C. Firanescu, A. Yang, L. Unipan, P. Duchambon, Y. Blouquit, C.T. Craesu: Calcium-dependent self-assembly of human centrin 2. J. Biol. Chem. 279(46), 47672 2004
S. Habelitz, A. Kullar, S.J. Marshall, P.K. DenBesten, M. Balooch, G.W. Marshall, W. Li: Amelogenin-guided crystal growth on fluoroapatite glass-ceramics. J. Dent. Res. 83(9), 698 2004
The presented study was supported by NIH/NIDCR Grants R01-DE17529 and R01-DE015821. The authors acknowledge the assistance of Xiaodong He for providing the AFM images of the assembly of pure rH174 and rH163 suspensions and H. Ewa Witkowska, Sarah Robinson, Venu Varanasi, Markus Hardt, and Steve Hall for the MALDI-TOF analyses. The UCSF Biomolecular Resource Center Mass Spectrometry facility was supported by a grant from the Sandler New Technology Fund.
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Uskoković, V., Kim, MK., Li, W. et al. Enzymatic processing of amelogenin during continuous crystallization of apatite. Journal of Materials Research 23, 3184–3195 (2008). https://doi.org/10.1557/JMR.2008.0387