Oligo( l -glutamic acids) in Calcium Phosphate Precipitation: Mechanism of Delayed Phase Transformation
Oligo( l -glutamic acids) in Calcium Phosphate Precipitation: Mechanism of Delayed Phase Transformation
复制标题
磷酸钙沉淀中的低聚（L-谷氨酸）：延迟相变机制
DOI：
10.1021/acs.jpcb.0c01690
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发表时间：
2020
期刊：
影响因子：
--
通讯作者：
Sahai, Nita
中科院分区：
文献类型：
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作者：
Ustriyana, Putu;Michel, F. Marc;Wilson, Michael C.;Harmon, Emma;Chen, Jiahui;Liu, Tianbo;Sahai, Nita
含有负电荷序列的蛋白质及其模拟物在天然和仿生矿化中是重要的。这些序列影响磷酸钙矿化的机制尚不清楚。在这里，含有不同数量的连续谷氨酸残基的重复单元的肽，寡（L-谷氨酸）n（n= 3，7，8，10），进行了研究，在延迟无定形磷酸钙（ACP）的结晶，同时保持溶液中的羧酸基团的量恒定的机制。增加肽链长度增加了溶液中一定总量羧酸基团下ACP的稳定性。这种效果被证明是由于更强的结合以及结合更多的钙离子每肽的较长的寡肽相比，较短的。有人建议，这些协会延迟的钙离子的结构重排和ACP的脱水，这是所需的羟基磷灰石的结晶。然而，ACP的初始成核和局部结构不随链长而变化。这两部分系列的第二部分提供了一个有机添加剂，特别是那些连续的酸性氨基酸序列，如何调节磷酸钙沉淀和相变的动力学机制的理解。
Proteins and their mimics that contain negatively charged sequences are important in natural and biomimetic mineralization. The mechanism by which these sequences affect calcium phosphate mineralization is not well understood. Here, peptides containing different numbers of repeat units of contiguous glutamic acid residues, oligo(l-glutamic acid)n(n= 3, 7, 8, 10), were investigated with regards to the mechanism in delaying the crystallization of amorphous calcium phosphate (ACP) while holding the amount of carboxylic acid groups in solution constant. Increasing peptide chain length increases the stability of ACP at a certain total amount of carboxylic acid groups in solution. This effect is shown to be due to stronger binding as well as binding to more calcium ions per peptide by the longer oligopeptides compared to the shorter ones. It is proposed that these associations delay the structural rearrangement of calcium ions and the dehydration of ACP, which are required for the crystallization of hydroxyapatite. The initial nucleation and the local structure of ACP, however, do not vary with chain length. This second part of a two-part series provides an improved mechanistic understanding of how organic additives, especially those with contiguous acidic amino acid sequences, modulate the kinetics of calcium phosphate precipitation and phase transformation.