Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA.
Microbial Sciences Institute, Yale University, New Haven, CT, USA.
Nat Chem Biol. 2020 Oct;16(10):1136-1142. doi: 10.1038/s41589-020-0623-9. Epub 2020 Aug 17.
Multifunctional living materials are attractive due to their powerful ability to self-repair and replicate. However, most natural materials lack electronic functionality. Here we show that an electric field, applied to electricity-producing Geobacter sulfurreducens biofilms, stimulates production of cytochrome OmcZ nanowires with 1,000-fold higher conductivity (30 S cm) and threefold higher stiffness (1.5 GPa) than the cytochrome OmcS nanowires that are important in natural environments. Using chemical imaging-based multimodal nanospectroscopy, we correlate protein structure with function and observe pH-induced conformational switching to β-sheets in individual nanowires, which increases their stiffness and conductivity by 100-fold due to enhanced π-stacking of heme groups; this was further confirmed by computational modeling and bulk spectroscopic studies. These nanowires can transduce mechanical and chemical stimuli into electrical signals to perform sensing, synthesis and energy production. These findings of biologically produced, highly conductive protein nanowires may help to guide the development of seamless, bidirectional interfaces between biological and electronic systems.
多功能活体材料因其强大的自修复和复制能力而备受关注。然而，大多数天然材料缺乏电子功能。在这里，我们展示了施加到发电的 Geobacter sulfurreducens 生物膜上的电场会刺激细胞色素 OmcZ 纳米线的产生，其导电性（30 S cm）比在自然环境中很重要的细胞色素 OmcS 纳米线高 1000 倍，刚性（1.5 GPa）高 3 倍。使用基于化学成像的多模态纳米光谱学，我们将蛋白质结构与功能相关联，并观察到 pH 诱导的构象转换为单个纳米线中的 β-折叠，由于血红素基团的增强 π-堆积，其刚性和导电性增加了 100 倍；这通过计算建模和体相光谱研究得到了进一步证实。这些纳米线可以将机械和化学刺激转化为电信号，从而进行传感、合成和能量产生。这些具有生物活性的高导电性蛋白质纳米线的发现可能有助于指导生物和电子系统之间无缝、双向界面的开发。
