Matrix Interactions in Biomineralization: Aragonite Nucleation by an Intrinsically Disordered Nacre Polypeptide, n16N, Associated with a β-Chitin Substrate
Matrix Interactions in Biomineralization: Aragonite Nucleation by an Intrinsically Disordered Nacre Polypeptide, n16N, Associated with a β-Chitin Substrate
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DOI：
10.1021/cg901389v
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发表时间：
2010-03-01
影响因子：
3.8
通讯作者：
Estroff, Lara A.
中科院分区：
文献类型：
--
作者：
Keene, Ellen C.;Evans, John S.;Estroff, Lara A.
Falini等人的先前文献表明，β-几丁质、蛋白质和丝纤蛋白样水凝胶之间的合作决定了软体动物壳的钠长石层内的多晶型选择性（有利于文石而不是方解石形成）。在这里，我们提出了一个体外试验中，我们结合联合收割机功能化的有机表面与可溶性肽探测碳酸钙多晶型物的选择性的表面肽相互作用的作用。具体而言，我们将n 16 N（来自日本珍珠蚌的30个氨基酸的肽）及其序列变体n 16 Ns（随机乱序）和n 16 NN（全局Asp -> Asn，Glu -> Gln取代）与不同形式的几丁质（α和β）组合。我们发现，吸附到β-甲壳素上的n 16 N的组合导致文石在体外的形成，以及其表现出的甲壳素结合能力。阴性对照，包括序列修饰形式的n16 N（n16 Ns和n16 NN），表现出P-几丁质结合和文石成核能力的变化。肽+ α-甲壳素组合表现出非常少的甲壳素结合，并且仅成核方解石，具有轻微的形态学影响。本研究中使用的n 16 N和n 16 Ns肽被认为是固有无序的，并且先前已显示与碳酸钙相互作用。我们提出，n16 N的内在无序结构也允许肽与底物相互作用，从而产生新的有机基质界面。多肽和底物之间的协同作用可以解释这些样品之间的多晶型特异性。
Previous literature by Falini et al. suggests that the cooperation between beta-chitin, proteins, and a silk fibroin-like hydrogel determines polymorph selectivity within the nacreous layer of mollusk shells (favoring aragonite over calcite formation). Here we present an in vitro assay in which we combine functionalized organic surfaces with soluble peptides to probe the role of surface-peptide interactions in calcium carbonate polymorph selectivity. Specifically, we combined n 16N (a 30 amino acid peptide from the Japanese pearl oyster Pinctada fucata) and its sequence variants, n 16Ns (randomly scrambled) and n 16NN (global Asp -> Asn, Glu -> Gin substitution), with different forms of chitin (alpha and beta). We found that the combination of n 16N adsorbed onto beta-chitin leads to the formation of aragonite in vitro as well its demonstrated chitin binding ability. Negative controls, including sequence modified versions of n 16N (n 16Ns and n 16NN), exhibit variation in P-chitin binding and the ability to nucleate aragonite. The peptide + alpha-chitin combination exhibits very little chitin binding and nucleates exclusively calcite with minor morphological effects. The n 16N and n 16Ns peptides used in this study are considered intrinsically disordered and have previously been shown to interact with calcium carbonate. We propose that the intrinsically disordered structure of n 16N also allows the peptide to interact with the Substrate creating it new organic matrix interface. The cooperation between the peptide and substrate may explain the polymorph specificity among these samples.