Jain Alok, Jochum Mara, Peter Christine
Max Planck Institute for Polymer Research , Ackermannweg 10, 55128 Mainz, Germany.
Langmuir. 2014 Dec 30;30(51):15486-95. doi: 10.1021/la503549q. Epub 2014 Dec 17.
Biomineralization is the intricate, biomedically highly relevant process by which living organisms deposit minerals on biological matrices to stiffen tissues and build skeletal structures and shells. Rapaport and coworkers ( J. Am. Chem. Soc. 2000 , 122 , 12523 ; Adv. Funct. Mater. 2008 , 18 , 2889 ; Acta Biomater. 2012 , 8 , 2466 ) have designed a class of self-assembling amphiphilic peptides that are capable of forming hydrogels and attracting ions from the environment, generating structures akin to the extracellular matrix and promoting bone regeneration. The air-water interface serves both in experiment and in simulations as a model hydrophobic surface to mimic the cell's organic-aqueous interface and to investigate the organization of the peptide matrix into ordered β-pleated monolayers and the subsequent onset of biomineral formation. To obtain insight into the underlying molecular mechanism, we have used molecular dynamics simulations to study the effect of peptide sequence on aggregate stability and ion-peptide interactions. We find-in excellent agreement with experimental observations-that the nature of the peptide termini (proline vs phenylalanine) affect the aggregate order, while the nature of the acidic side chains (aspartic vs glutamic acid) affect the aggregate's stability in the presence of ions. These simulations provide valuable microscopic insight into the way ions and peptide templates mutually affect each other during the early stages of biomineralization preceding nucleation.
生物矿化是一个复杂且与生物医学高度相关的过程，通过这个过程，生物体在生物基质上沉积矿物质，以强化组织并构建骨骼结构和外壳。拉帕波特及其同事（《美国化学会志》，2000年，第122卷，第12523页；《先进功能材料》，2008年，第18卷，第2889页；《生物材料学报》，2012年，第8卷，第2466页）设计了一类自组装两亲性肽，这类肽能够形成水凝胶并从环境中吸引离子，生成类似于细胞外基质的结构，并促进骨再生。在实验和模拟中，气 - 水界面都作为一个模型疏水表面，用于模拟细胞的有机 - 水界面，并研究肽基质组织成有序的β - 折叠单层以及随后生物矿化开始的情况。为了深入了解潜在的分子机制，我们使用分子动力学模拟来研究肽序列对聚集体稳定性和离子 - 肽相互作用的影响。我们发现——与实验观察结果高度一致——肽末端的性质（脯氨酸与苯丙氨酸）影响聚集体的有序性，而酸性侧链的性质（天冬氨酸与谷氨酸）在有离子存在的情况下影响聚集体的稳定性。这些模拟为成核前生物矿化早期阶段离子和肽模板相互影响的方式提供了有价值的微观见解。
