EVIDENCE FOR AMELOGENIN NANOSPHERES AS FUNCTIONAL COMPONENTS OF SECRETORY-STAGE ENAMEL MATRIX
EVIDENCE FOR AMELOGENIN NANOSPHERES AS FUNCTIONAL COMPONENTS OF SECRETORY-STAGE ENAMEL MATRIX
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DOI：
10.1006/jsbi.1995.1029
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发表时间：
1995-07-01
影响因子：
3
通讯作者：
SLAVKIN, HC
中科院分区：
文献类型：
--
作者：
FINCHAM, AG;MORADIANOLDAK, J;SLAVKIN, HC
釉原蛋白是牙釉质发育过程中细胞外基质的主要蛋白质，被认为在牙齿发育的生物矿化过程中起作用，但其分子机制尚不清楚。最近的成像研究，采用动态光散射，原子力，和透射电子显微镜（TEM）显示，重组釉原蛋白（M（r）类似于20 000 Da）自发形成超分子准球形聚集体（“纳米球”）的直径为15-20 nm。通过与采用重组釉原蛋白的体外实验进行比较，我们表明，纳米球出现电子透明的结构时，与传统的电子显微镜造影剂（磷钨酸盐或醋酸铀酰），我们推测，这种属性来自釉原蛋白的疏水性。采用TEM制剂，从小鼠，牛和仓鼠的釉质发育，我们证明了釉原蛋白纳米球发生的电子透明结构对齐，并分离，釉质矿物微晶珠行。我们假设，釉原蛋白单体自组装形成纳米球的功能，空间的初始微晶，控制晶体习性，抑制晶间融合，并通过其表面的并置，创造阴离子通道，促进离子运输内的矿化基质。(C)出版社：Academic Press
Amelogenins are the principal proteins of the extracellular matrix of developing dental enamel and are postulated to function in the processes of biomineralization of the developing tooth although the molecular mechanisms concerned are poorly understood. Recent imaging studies, employing dynamic light scattering, atomic force, and transmission electron microscopy (TEM) have shown that a recombinant amelogenin (M(r) similar to 20 000 Da) spontaneously forms supramolecular quasi-spherical aggregates (''nanospheres'') of 15-20 nm in diameter. By comparison with in vitro experiments employing the recombinant amelogenin we show that the nanospheres appear as electron-lucent structures when treated with conventional electron microscopy contrast reagents (phosphotungstate or uranyl acetate) and we speculate that this property derives from the hydrophobic nature of the amelogenin protein. Employing TEM preparations, developing enamel from mouse, bovine, and hamster we demonstrate that the amelogenin nanospheres occur as beaded rows of electron-lucent structures aligned with, and separating, the enamel mineral crystallites. We postulate that the amelogenin monomers self-assemble to form nanospheres which function to space the initial crystallites, control crystal habit, inhibit intercrystalline fusions, and, through the apposition of their surfaces, create anionic channels which facilitate ion transport within the mineralizing matrix. (C) 1995 Academic Press, Inc.