In situ AFM study of amelogenin assembly and disassembly dynamics on charged surfaces provides insights on matrix protein self-assembly.
In situ AFM study of amelogenin assembly and disassembly dynamics on charged surfaces provides insights on matrix protein self-assembly.
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DOI：
10.1021/ja206849c
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发表时间：
2011-11-02
影响因子：
15
通讯作者：
DeYoreo, James J.
中科院分区：
文献类型：
--
作者：
Chen, Chun-Long;Bromley, Keith M.;Moradian-Oldak, Janet;DeYoreo, James J.
由于基质蛋白的自组装是硬组织矿化的关键步骤，因此了解组装途径和潜在机制可能对硬组织工程的成功至关重要。虽然基质蛋白组装的许多研究都是在散装溶液中进行的，但在体内，这些蛋白质很可能与由脂质、蛋白质或矿物质组成的带电生物表面接触。在这里，我们报告了一项原位原子力显微镜研究的结果，研究了在釉质发育过程中细胞外基质的主要蛋白——淀粉原蛋白与两种不同的带电基质——亲水性带负电的裸云母和带正电的3-氨基丙基三乙氧基硅烷（APS）硅化云母——接触时的自组装。首先，我们展示了一种基于afm的方案，用于确定淀粉原单体和低聚物的大小。使用该方案，我们发现，尽管在DLS研究的pH8.0的体溶液中，淀粉原蛋白主要以直径为~ 26 nm的纳米球存在，但在相同pH下，它与带电底物相互作用时表现出显著不同的行为，并表现出复杂的底物依赖的组装途径和动力学。在带正电的aps处理的云母表面，淀粉原蛋白形成相对均匀的十聚体，然后转变为两个主要群体：低聚物和淀粉原蛋白单体的高阶组装，而在带负电的裸云母表面，它形成一层单体膜，表现出尖诱导的脱附和图案。目前的研究代表了一个成功的尝试，以确定淀粉原蛋白低聚物的大小，并直接监测组装和拆卸动力学的表面。这一发现对体外淀粉原控制的磷酸钙矿化具有重要意义，并可能为体内基质蛋白的自组装及其对硬组织形成的控制提供新的见解。
Because self-assembly of matrix proteins is a key step in hard tissue mineralization, developing an understanding of the assembly pathways and underlying mechanisms is likely to be important for successful hard tissue engineering. While many studies of matrix protein assembly have been performed on bulk solutions, in vivo these proteins are likely to be in contact with charged biological surfaces composed of lipids, proteins, or minerals. Here we report the results of an in situ AFM study of self-assembly by amelogenin - the principal protein of the extracellular matrix in developing enamel - in contact with two different charged substrates: hydrophilic negatively charged bare mica and positively charged 3-aminopropyl triethoxysilane (APS) silanized mica. First we demonstrate an AFM-based protocol for determining the size of both amelogenin monomers and oligomers. Using this protocol, we find that, although amelogenin exists primarily as ∼26 nm in diameter nanospheres in bulk solution at pH8.0 studied by DLS, it behaves dramatically differently upon interacting with charged substrates at the same pH, and exhibits complex substrate-dependent assembly pathways and dynamics. On positively charged APS-treated mica surfaces, amelogenin forms a relatively uniform population of decameric oligomers which then transforms into two main populations: higher-order assemblies of oligomers and amelogenin monomers, while on negatively charged bare mica surfaces, it forms a film of monomers that exhibits tip-induced desorption and patterning. The present study represents a successful attempt to identify the size of amelogenin oligomers and to directly monitor assembly and disassembly dynamics on surfaces. The findings have implications for amelogenin-controlled calcium phosphate mineralization in vitro and may offer new insights into in vivo self-assembly of matrix proteins, as well as their control over hard tissue formation.
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DOI：
10.1002/anie.201100181
发表时间：
2011-08-08
期刊：
Angewandte Chemie (International ed. in English)
影响因子：
--
作者：
Friddle RW;Battle K;Trubetskoy V;Tao J;Salter EA;Moradian-Oldak J;De Yoreo JJ;Wierzbicki A
通讯作者：
Wierzbicki A
影响因子：
2.9
作者：
Buchko, Garry W.;Tarasevich, Barbara J.;Bekhazi, Jacky;Snead, Malcolm L.;Shaw, Wendy J.
通讯作者：
Shaw, Wendy J.
影响因子：
14
作者：
Fan, Yuwei;Sun, Zhi;Moradian-Oldak, Janet
通讯作者：
Moradian-Oldak, Janet
影响因子：
3
作者：
Fan D;Du C;Sun Z;Lakshminarayanan R;Moradian-Oldak J
通讯作者：
Moradian-Oldak J
影响因子：
6.2
作者：
Aichmayer, Barbara;Wiedemann-Bidlack, Felicitas B.;Gilow, Christoph;Simmer, James P.;Yamakoshi, Yasuo;Emmerling, Franziska;Margolis, Henry C.;Fratzl, Peter
通讯作者：
Fratzl, Peter