Amyloid-like ribbons of amelogenins in enamel mineralization.
Amyloid-like ribbons of amelogenins in enamel mineralization.
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DOI：
10.1038/srep23105
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发表时间：
2016-03-24
影响因子：
4.6
通讯作者：
Habelitz S
中科院分区：
文献类型：
--
作者：
Carneiro KM;Zhai H;Zhu L;Horst JA;Sitlin M;Nguyen M;Wagner M;Simpliciano C;Milder M;Chen CL;Ashby P;Bonde J;Li W;Habelitz S
牙釉质是牙齿的最外层，是一种无法再生的无细胞矿化组织；成熟的组织由高长径比的磷灰石纳米晶体组成，这些晶体排列成釉柱和柱间区域。釉原蛋白在发育中的牙釉质中占蛋白质基质的90%，在引导成熟牙釉质中所观察到的磷灰石晶体的分级组织方面起着核心作用。到目前为止，釉原蛋白的超分子结构与成熟牙釉质之间令人信服的联系尚未被描述，部分原因是蛋白质基质在组织成熟过程中会降解。在此我们展示了令人信服的证据，表明釉原蛋白在体外和体内可自组装成类似淀粉样的结构。我们发现牙釉质基质对淀粉样物质呈阳性染色，并且我们确定了釉原蛋白内可自组装成β -折叠的一个特定区域。我们提出釉原蛋白纳米带为人类牙釉质中磷灰石矿物质的生长提供模板。这是对当前牙釉质发育模型的一种范式转变。
Enamel, the outermost layer of teeth, is an acellular mineralized tissue that cannot regenerate; the mature tissue is composed of high aspect ratio apatite nanocrystals organized into rods and inter-rod regions. Amelogenin constitutes 90% of the protein matrix in developing enamel and plays a central role in guiding the hierarchical organization of apatite crystals observed in mature enamel. To date, a convincing link between amelogenin supramolecular structures and mature enamel has yet to be described, in part because the protein matrix is degraded during tissue maturation. Here we show compelling evidence that amelogenin self-assembles into an amyloid-like structure in vitro and in vivo. We show that enamel matrices stain positive for amyloids and we identify a specific region within amelogenin that self-assembles into β-sheets. We propose that amelogenin nanoribbons template the growth of apatite mineral in human enamel. This is a paradigm shift from the current model of enamel development.