The cooperative self-assembly of 25 and 23kDa amelogenins.
The cooperative self-assembly of 25 and 23kDa amelogenins.
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DOI：
10.1016/j.jsb.2008.09.005
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发表时间：
2008-12
影响因子：
3
通讯作者：
Habelitz, Stefan
中科院分区：
文献类型：
--
作者：
He, Xiaodong;Li, Wu;Habelitz, Stefan
细胞外基质蛋白牙釉蛋白的自组装被认为在牙釉质形成过程中调节牙釉质晶体的生长和组织中发挥重要作用。全长牙釉蛋白独特地调节牙釉质晶体的生长、形状和排列。蛋白质水解最终将促进组织具有高矿物质含量。然而，蛋白质加工具有高度特异性，表明裂解的牙釉蛋白在牙釉质成熟中发挥功能作用。在这里，我们假设重组全长牙釉蛋白 25 kDa 和 23 kDa 蛋白水解裂解产物的协同自组装是 pH、混合比例和孵育时间的函数，并且与蛋白质的等电点相关。通过原子力显微镜观察到牙釉蛋白自组装成纳米球，纳米球的尺寸随着pH值的增加而增加。牙釉蛋白 25 和 23 kDa 在几天内主要在 pH 值分别为 6.5 和 7.5 时形成约 100 nm 长和 25 nm 宽的细长结构。当 25 kDa 和 23 kDa 的蛋白质混合时，在 7.0 左右的 pH 值下，24 小时内获得了由融合纳米球组成的长度为 200-300 nm 的自组装纳米线。随着时间的推移，蛋白质纳米线形成链接，7 天后获得连续的网格。当两种牙釉蛋白混合在溶液中时，电导率数据也显示出逐渐变化，这支持了在较长时间内形成细长结构的想法。我们提出，由于等电点的差异，由 23 或 25 kDa 牙釉蛋白组成的自组装纳米球在 pH 值约为 7.0 时具有相反的离子电荷，从而经历离子吸引力，从而实现协作自组装。
Self-assembly of the extracellular matrix protein amelogenin is believed to play an essential role in regulating the growth and organization of enamel crystals during enamel formation. The full-length amelogenin uniquely regulates the growth, shape, and arrangement of enamel crystals. Protein hydrolysis will ultimately facilitate a tissue with high mineral content. Protein processing is however highly specific suggesting a functional role of the cleaved amelogenins in enamel maturation. Here we hypothesize that the cooperative self-assembly of the recombinant full-length amelogenin 25 kDa and the 23 kDa proteolytic cleavage product is a function of pH, mixing ratio and incubation time and is associated with the isoelectric point of the protein. Self-assembly of amelogenin into nanospheres which increased in size with increasing pH was observed by atomic force microscopy. Elongated structures of about 100nm length and 25 nm width formed over several days for amelogenin 25 and 23 kDa predominantly at pH-values of 6.5 and 7.5, respectively. When both proteins 25 and 23 kDa were mixed, self-assembled nanostrings of 200–300 nm length consisting of fused nanospheres were obtained at pH around 7.0 within 24 h. The protein nanostrings formed links over time and a continuous mesh was obtained after 7 days. Electrical conductivity data also showed gradual changes when both amelogenins were mixed in solutions supporting the idea that elongated structures form over extended periods of time. We propose that due to the difference in the isoelectric point, self-assembled nanospheres composed of 23 or 25 kDa amelogenin have opposite ionic charges at pH-values around 7.0 and thus experience ionic attraction that enables cooperative self-assembly.
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影响因子：
7.6
作者：
Bouropoulos, N;Moradian-Oldak, J
通讯作者：
Moradian-Oldak, J
影响因子：
15
作者：
Aggeli, A;Bell, M;Boden, N
通讯作者：
Boden, N
影响因子：
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作者：
UCHIDA, T;TANABE, T;SHIMIZU, M
通讯作者：
SHIMIZU, M
影响因子：
3
作者：
Balooch, M.;Habelitz, S.;Marshall, G. W.
通讯作者：
Marshall, G. W.
影响因子：
3
作者：
FINCHAM, AG;MORADIANOLDAK, J;SLAVKIN, HC
通讯作者：
SLAVKIN, HC