Department of Materials Science and Technology, University of Crete, Vassilika Vouton, Greece.
Biopolymers. 2012;98(6):501-9. doi: 10.1002/bip.22091.
Self-assembling biological materials increasingly serve as templates for the binding of inorganic materials and fabrication of composite nanowires, tubes, etc. with important applications in nanobiotechnology. We have previously reported the use of a self-assembling octapeptide building block as scaffold for the systematic introduction of metal-binding residues, namely cysteines, at the first two amino acids within the sequence (Kasotakis et al., Biopolymers 2009, 92, 164-172). We have also reported unexpected behavior of serine within the octapeptide NH₂ − NSGAITIG − CONH₂( (Asparagine-Serine-Glycine-Alanine-Isoleucine-Threonine-Isoleucine-Glycine) in nucleating gold and platinum nanoparticles. Herein, we report that this serine residue is instrumental in nucleating silica nanoparticles on the surface of the self-assembled fibrils from TEOS (tetraethyl orthosilicate) precursors. We carried out a systematic investigation of the adjacent functionalities and we propose that this serine residue is rendered abnormally nucleophilic through proton abstraction by the N-terminal amino group of the peptide. Peptides with a threonine or a cysteine residue at position 2 are also able to nucleate silica nanoparticles. We propose that rationally designed self-assembling peptides bearing hydroxyl groups adjacent to free amine functionalities could be used for targeted templating of biogenic and even nonbiogenic oxides.
自组装生物材料越来越多地作为结合无机材料和制造复合纳米线、纳米管等的模板，在纳米生物技术中有重要的应用。我们之前报道过使用自组装的八肽构建块作为支架，在序列的前两个氨基酸处系统引入金属结合残基，即半胱氨酸（Kasotakis 等人，Biopolymers 2009, 92, 164-172）。我们还报道了八肽 NH₂−NSGAITIG−CONH₂（(天冬酰胺-丝氨酸-甘氨酸-丙氨酸-异亮氨酸-苏氨酸-异亮氨酸-甘氨酸)中的丝氨酸在金和铂纳米粒子成核中的意外行为。在此，我们报告说，这种丝氨酸残基在自组装纤维表面上从 TEOS（正硅酸乙酯）前体成核二氧化硅纳米粒子中起着重要作用。我们进行了系统的相邻官能团的研究，并提出，这种丝氨酸残基通过肽的 N 端氨基的质子抽提而呈现出异常的亲核性。在位置 2 处具有苏氨酸或半胱氨酸残基的肽也能够成核二氧化硅纳米粒子。我们提出，合理设计的带有相邻游离胺官能团的羟基的自组装肽可用于生物甚至非生物氧化物的靶向模板。
