Synergistic Biomineralization Phenomena Created by a Combinatorial Nacre Protein Model System.
Synergistic Biomineralization Phenomena Created by a Combinatorial Nacre Protein Model System.
复制标题
DOI：
10.1021/acs.biochem.6b00163
复制
发表时间：
2016-04-26
期刊：
影响因子：
2.9
通讯作者：
Evans JS
中科院分区：
文献类型：
--
作者：
Chang EP;Roncal-Herrero T;Morgan T;Dunn KE;Rao A;Kunitake JA;Lui S;Bilton M;Estroff LA;Kröger R;Johnson S;Cölfen H;Evans JS
在软体动物贝壳的珍珠层或文石层中存在蛋白质组，这些蛋白质组既调节珍珠层成核的早期阶段，也调节由矿物纳米颗粒前体形成的珍珠片剂的纳米到中尺度的组装。已经开发了几种方法来了解与蛋白质相关的珍珠层形成机制，但我们仍然缺乏对蛋白质系综或蛋白质组如何管理成核和晶体生长的了解。为了提供更多的见解，我们创建了一个比例定义的组合模型，由两个珍珠层相关蛋白组成，C-环AP7(贝壳珍珠层，H.rufescens)和伪EF手PFMG1(牡蛎珍珠层，P.fescens)，它们各自的体外矿化功能都是有据可查的，而且彼此不同。通过扫描电子显微镜、流动细胞扫描电子显微镜、原子力显微镜、Ca(II)电位滴定和QCM-D定量分析，我们发现两种珍珠层蛋白在相同的矿化环境下都具有功能活性，并且在摩尔比为1：1的情况下，协同地生成了具有有序晶内纳米孔的碳酸钙介观结构，显著延长了成核时间，并引入了额外的成核事件。此外，这两种蛋白质共同产生纳米级的蛋白质聚集体或相，在矿化条件下进一步组装成具有增强ACC稳定能力的蛋白质-矿物PILP样相，并且在这些条件下AP7和PFMG1之间存在分子间相互作用的证据。因此，由一种以上已定义的生物矿化蛋白组成的组合模型系统极大地改变了体外生物矿化过程的结果。
In the nacre or aragonite layer of the mollusk shell there exist proteomes which regulate both the early stages of nucleation and nano-to-mesoscale assembly of nacre tablets from mineral nanoparticle precursors. Several approaches have been developed to understand protein-associated mechanisms of nacre formation, yet we still lack insight into how protein ensembles or proteomes manage nucleation and crystal growth. To provide additional insights we have created a proportionally-defined combinatorial model consisting of two nacre-associated proteins, C-RING AP7 (shell nacre, H. rufescens) and pseudo-EF hand PFMG1 (oyster pearl nacre, P. fucata) whose individual in vitro mineralization functionalities are well-documented and distinct from one another. Using SEM, flow cell STEM, AFM, Ca(II) potentiometric titrations and QCM-D quantitative analyses, we find that both nacre proteins are functionally active within the same mineralization environments, and at 1:1 mole ratios, synergistically create calcium carbonate mesoscale structures with ordered intracrystalline nanoporosities, extensively prolong nucleation times and introduce an additional nucleation event. Further, these two proteins jointly create nanoscale protein aggregates or phases that under mineralization conditions further assemble into protein-mineral PILP-like phases with enhanced ACC stabilization capabilities, and there is evidence for intermolecular interactions between AP7 and PFMG1 under these conditions. Thus, a combinatorial model system consisting of more than one defined biomineralization protein dramatically changes the outcome of the in vitro biomineralization process.