Habelitz S, Kullar A, Marshall S J, DenBesten P K, Balooch M, Marshall G W, Li W
Department of Preventive and Restorative Dental Sciences, University of California, 707 Parnassus Avenue, D-2260, San Francisco 94143-0758, USA.
J Dent Res. 2004 Sep;83(9):698-702. doi: 10.1177/154405910408300908.
The formation of aligned fibrous apatite crystals in enamel is predominantly attributed to the involvement of amelogenin proteins. We developed a model to study interactions of matrix proteins with apatite mineral in vitro and tested the hypothesis that amelogenin solubility affects the ability to induce protein-guided mineralization. Crystal growth experiments were performed on fluoroapatite (FAP) glass-ceramics in mineralizing solutions containing recombinant full-length amelogenin (rH174) at different concentrations. Using atomic force microscopy, we observed that mineral precipitated randomly on the substrate, but also formed thin layers (height, 10 nm) on FAP within 24 hrs. This growth pattern was unaffected when 0.4 mg/mL of rH174 was added. In contrast, crystals grew on FAP at a rate up to 20 times higher, at 1.6 mg/mL protein. Furthermore, nanospheres and mineral bound specifically to FAP and aligned in strings approximately parallel to the c-axis of FAP, leading us to the conclusion that amelogenin proteins indeed control direction and rate of growth of apatite in enamel.
牙釉质中排列整齐的纤维状磷灰石晶体的形成主要归因于釉原蛋白的作用。我们建立了一个模型来研究基质蛋白与磷灰石矿物在体外的相互作用，并验证了釉原蛋白溶解度影响诱导蛋白引导矿化能力的假设。在含有不同浓度重组全长釉原蛋白（rH174）的矿化溶液中，对氟磷灰石（FAP）微晶玻璃进行晶体生长实验。使用原子力显微镜，我们观察到矿物在基质上随机沉淀，但在24小时内在FAP上也形成了薄层（高度为10纳米）。添加0.4毫克/毫升的rH174时，这种生长模式不受影响。相比之下，当蛋白浓度为1.6毫克/毫升时，晶体在FAP上的生长速度提高了20倍。此外，纳米球和矿物质特异性结合到FAP上，并排列成大致平行于FAP c轴的链状，这使我们得出结论，釉原蛋白确实控制着牙釉质中磷灰石的生长方向和速度。
