Hellner Brittney, Stegmann Amy E, Pushpavanam Karthik, Bailey Matthew J, Baneyx François
Department of Chemical Engineering, University of Washington, P.O. Box 351750, Seattle, Washington 98195, United States.
Department of Chemical Engineering and Molecular Engineering & Sciences Institute, University of Washington, P.O. Box 351750, Seattle, Washington 98195, United States.
Langmuir. 2020 Jul 28;36(29):8503-8510. doi: 10.1021/acs.langmuir.0c01108. Epub 2020 Jul 16.
The biomimetic route to inorganic synthesis presents an opportunity to produce complex materials with superior properties under ambient conditions and from nontoxic precursors. While there has been significant progress in using solid-binding peptides (SBPs), proteins, and organisms to produce a variety of inorganic and hybrid structures, it has been more challenging to understand the interplay of solution conditions and solid-binding peptide (SBP) sequence, structure, and self-association on synthetic outcomes. Here, we show that fusing the Car9 silica-binding peptide-but not the silaffin-derived R5 peptide-to superfolder green fluorescent protein (sfGFP) enhances the ability of micromolar concentrations of protein to induce rapid titania (TiO) precipitation from acidified solutions of tetrakis(di-lactato)-oxo-titanate (TiBALDH). TiO is produced stoichiometrically and although predominantly amorphous, contains nanosized anatase and monoclinic TiO() inclusions. Remarkably, the phase of these nanocrystallites can be tuned from about 80% TiO() to about 65% anatase by using Car9 mutants impaired in their ability to drive the formation of higher-order sfGFP-Car9 oligomers. Our results suggest that the presentation of multiple basic side chains in an extended plane formed by SBP self-association is critical to template the formation of monoclinic crystallites and underscore the subtle influence that single or dual substitutions in dodecameric SBPs can exert on the yield and crystallinity of biomineralized inorganics.
无机合成的仿生途径为在环境条件下从无毒前体生产具有优异性能的复杂材料提供了契机。虽然在使用固体结合肽（SBP）、蛋白质和生物体来生产各种无机和杂化结构方面已经取得了显著进展，但要理解溶液条件与固体结合肽（SBP）序列、结构和自缔合对合成结果的相互作用则更具挑战性。在此，我们表明，将Car9二氧化硅结合肽而非硅素衍生的R5肽与超折叠绿色荧光蛋白（sfGFP）融合，可增强微摩尔浓度的蛋白质从四（二乳酸根） - 氧代钛酸（TiBALDH）的酸化溶液中诱导快速二氧化钛（TiO₂）沉淀的能力。TiO₂按化学计量生成，虽然主要为无定形，但含有纳米尺寸的锐钛矿和单斜TiO₂夹杂物。值得注意的是，通过使用在驱动高阶sfGFP - Car9寡聚体形成能力上受损的Car9突变体，这些纳米晶体的相可以从约80%的TiO₂调整到约65%的锐钛矿。我们的结果表明，由SBP自缔合形成的扩展平面中多个碱性侧链的呈现对于模板化单斜微晶的形成至关重要，并强调了十二聚体SBP中的单取代或双取代对生物矿化无机物的产量和结晶度可能产生的微妙影响。
