Department of Chemistry, University of Washington , Box 351700, Seattle, Washington 98195, United States.
Langmuir. 2017 Oct 10;33(40):10517-10524. doi: 10.1021/acs.langmuir.7b01048. Epub 2017 Sep 25.
A biomimetic, peptide-mediated approach to inorganic nanostructure formation is of great interest as an alternative to industrial production methods. To investigate the role of peptide structure on silica (SiO) and titania (TiO) morphologies, we use the R5 peptide domain derived from the silaffin protein to produce uniform SiO and TiO nanostructures from the precursor silicic acid and titanium bis(ammonium lactato)dihydroxide, respectively. The resulting biosilica and biotitania nanostructures are characterized using scanning electron microscopy. To investigate the process of R5-mediated SiO and TiO formation, we carry out 1D and 2D solid-state NMR (ssNMR) studies on R5 samples with uniformly C- and N-labeled residues to determine the backbone and side-chain chemical shifts. C chemical shift data are in turn used to determine peptide backbone torsion angles and secondary structure for the R5 peptide neat, in silica, and in titania. We are thus able to assess the impact of the different mineral environments on peptide structure, and we can further elucidate from C chemical shifts change the degree to which various side chains are in close proximity to the mineral phases. These comparisons add to the understanding of the role of R5 and its structure in both SiO and TiO formation.
仿生肽介导的无机纳米结构形成方法作为工业生产方法的替代方法具有重要意义。为了研究肽结构对二氧化硅 (SiO) 和二氧化钛 (TiO) 形态的作用，我们使用源自丝氨酸蛋白酶的 R5 肽结构域，分别由硅酸前体和钛双（氨乳酸）二氢氧化物制备均匀的 SiO 和 TiO 纳米结构。使用扫描电子显微镜对所得生物硅和生物钛纳米结构进行了表征。为了研究 R5 介导的 SiO 和 TiO 形成过程，我们对具有均匀 C 和 N 标记残基的 R5 样品进行了一维和二维固态 NMR（ssNMR）研究，以确定主链和侧链化学位移。C 化学位移数据又用于确定 R5 肽在纯态、SiO 中和 TiO 中的肽主链扭转角和二级结构。因此，我们能够评估不同矿物环境对肽结构的影响，并可以进一步从 C 化学位移变化中阐明各种侧链与矿物相的接近程度。这些比较有助于理解 R5 及其在 SiO 和 TiO 形成中的结构的作用。
