title: Enzymatic Processing of Amelogenin during Continuous Crystallization of Apatite.
abstract: Dental enamel forms through a protein-controlled mineralization and enzymatic degradation 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 employed 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 an interaction between rH174 and the proteolytic cleavage products. Despite continuous titration, the levels of calcium exhibited a consistent trend of decreasing, thereby indicating its possible role in the 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.
authors.affiliation: Division of Biomaterials and Bioengineering, Department of Preventive and Restorative Dental Sciences, University of California, San Francisco.
authors.forename: V
authors.initials: V
authors.lastname: Uskoković
authors.forename: M-K
authors.initials: MK
authors.lastname: Kim
authors.forename: W
authors.initials: W
authors.lastname: Li
authors.forename: S
authors.initials: S
authors.lastname: Habelitz