Yamashita Tatsuya, Matsuda Hiroki, Koizumi Kyohei, Thirumalaisamy Logu, Kim Myeongok, Negishi Lumi, Kurumizaka Hitoshi, Tominaga Yoriko, Takagi Yoshihiro, Takai Ken, Okumura Taiga, Katayama Hidekazu, Horitani Masaki, Ahsan Nazmul, Okada Yoshitaka, Nagata Koji, Suzuki Yohey, Suzuki Michio
Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, the University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo, 113-8657, Japan.
Research Center for Advanced Science and Technology (RCAST), the University of Tokyo, 4-6-1 Komaba, Meguro, Tokyo, 153-8904, Japan.
Acta Biomater. 2023 May;162:110-119. doi: 10.1016/j.actbio.2023.03.005. Epub 2023 Mar 15.
The scaly-foot gastropod (Chrysomallon squamiferum), which lives in the deep-sea zone of oceans around thermal vents, has a black shell and scales on the foot. Both the black shell and scales contain iron sulfide minerals such as greigite (FeS) and pyrite (FeS). Although pyrite nanoparticles can be used as materials for solar panels, it is difficult to synthesize stable and spherical nanoparticles in vitro. In this study, we extracted organic molecules that interact with nano-pyrite from the shell of the scaly-foot gastropod to develop a low-cost, eco-friendly method for pyrite nanoparticles synthesis. Myoglobin (csMG), a heme protein, was identified in the iron sulfide layer of the shell. We purified recombinant csMG (r-csMG) and demonstrated that r-csMG helped in the conversion of ferric ions, sulfide ions and sulfur into spherical shaped pyrite nanoparticles at 80°C. To reduce the effort and cost of production, we showed that commercially available myoglobin from Equus caballus (ecMG) also induced the in vitro synthesis of pyrite nanoparticles. Using structure-function experiments with digested peptides, we highlighted that the amino acid sequence of r-csMG peptides controlled the spherical shape of the nanoparticle while the hemin molecules, which the peptides interacted with, maintained the size of nanoparticles. Synthesized pyrite nanoparticles exhibited strong photoluminescence in the visible wavelength region, suggesting its potential application as a photovoltaic solar cell material. These results suggest that materials for solar cells can be produced at low cost and energy under eco-friendly conditions. STATEMENT OF SIGNIFICANCE: Pyrite is a highly promising material for photovoltaic devices because of its excellent optical, electrical, magnetic, and transport properties and high optical absorption coefficient. Almost all current pyrite synthesis methods use organic solvents at high temperature and pressure under reducing conditions. Synthesized pyrite nanoparticles are unstable and are difficult to use in devices. The scaly-foot gastropod can synthesize pyrite nanoparticles in vivo, meaning that pyrite nanoparticles can be generated in an aqueous environment at low temperature. In this study, we demonstrated the synthesis of pyrite nanoparticles using a heme protein identified in the iron sulfide layer of the scaly-foot gastropod shell. These results exemplify how natural products in organisms can inspire the innovation of new technology.
鳞脚腹足类动物（学名：Chrysomallon squamiferum）生活在热液喷口附近的海洋深海区域，其外壳呈黑色，足部有鳞片。黑色外壳和鳞片都含有硫化铁矿物，如硫复铁矿（FeS）和黄铁矿（FeS）。尽管黄铁矿纳米颗粒可用于制造太阳能电池板材料，但在体外很难合成稳定的球形纳米颗粒。在本研究中，我们从鳞脚腹足类动物的外壳中提取了与纳米黄铁矿相互作用的有机分子，以开发一种低成本、环保的黄铁矿纳米颗粒合成方法。我们在外壳的硫化铁层中鉴定出一种血红素蛋白——肌红蛋白（csMG）。我们纯化了重组csMG（r-csMG），并证明r-csMG有助于在80°C条件下将铁离子、硫离子和硫转化为球形黄铁矿纳米颗粒。为了降低生产难度和成本，我们发现市售的马（Equus caballus）肌红蛋白（ecMG）也能诱导体外合成黄铁矿纳米颗粒。通过对消化后的肽段进行结构-功能实验，我们发现r-csMG肽段的氨基酸序列控制着纳米颗粒的球形形状，而肽段与之相互作用的血红素分子则维持着纳米颗粒的大小。合成的黄铁矿纳米颗粒在可见光波长区域表现出强烈的光致发光，表明其作为光伏太阳能电池材料具有潜在应用价值。这些结果表明，可以在环保条件下以低成本和低能耗生产太阳能电池材料。重要性声明：黄铁矿因其优异的光学、电学、磁学和传输特性以及高光学吸收系数，是一种极有前景的光伏器件材料。目前几乎所有的黄铁矿合成方法都在还原条件下的高温高压下使用有机溶剂。合成的黄铁矿纳米颗粒不稳定，难以用于器件。鳞脚腹足类动物能够在体内合成黄铁矿纳米颗粒，这意味着黄铁矿纳米颗粒可以在低温的水性环境中生成。在本研究中，我们展示了利用在鳞脚腹足类动物外壳的硫化铁层中鉴定出的一种血红素蛋白来合成黄铁矿纳米颗粒。这些结果例证了生物体中的天然产物如何激发新技术的创新。
