Cho Se Youn, Yun Young Soo, Lee Sungho, Jang Dawon, Park Kyu-Young, Kim Jae Kyung, Kim Byung Hoon, Kang Kisuk, Kaplan David L, Jin Hyoung-Joon
Department of Polymer Science and Engineering, Inha University, Incheon 402-751, Korea.
1] Carbon Convergence Materials Research Center, Korea Institute of Science and Technology, San 101 Enha-ri, Bongdong-eup, Wanju-gun 565-905, Korea [2] Department of Nano Material Engineering, Korea University of Science and Technology, 217 Gajeong-ro, Yusung-gu, Daejeon 305-350, Korea.
Nat Commun. 2015 May 20;6:7145. doi: 10.1038/ncomms8145.
Silk proteins are of great interest to the scientific community owing to their unique mechanical properties and interesting biological functionality. In addition, the silk proteins are not burned out following heating, rather they are transformed into a carbonaceous solid, pyroprotein; several studies have identified potential carbon precursors for state-of-the-art technologies. However, no mechanism for the carbonization of proteins has yet been reported. Here we examine the structural and chemical changes of silk proteins systematically at temperatures above the onset of thermal degradation. We find that the β-sheet structure is transformed into an sp(2)-hybridized carbon hexagonal structure by simple heating to 350 °C. The pseudographitic crystalline layers grew to form highly ordered graphitic structures following further heating to 2,800 °C. Our results provide a mechanism for the thermal transition of the protein and demonstrate a potential strategy for designing pyroproteins using a clean system with a catalyst-free aqueous wet process for in vivo applications.
由于其独特的机械性能和有趣的生物功能，丝蛋白引起了科学界的极大兴趣。此外，丝蛋白在加热后不会被烧掉，而是会转化为一种含碳固体——焦蛋白；多项研究已经确定了用于先进技术的潜在碳前体。然而，尚未有关于蛋白质碳化机制的报道。在这里，我们系统地研究了丝蛋白在高于热降解起始温度的温度下的结构和化学变化。我们发现，通过简单加热至350°C，β-折叠结构会转变为sp(2)杂化的碳六边形结构。进一步加热至2800°C后，准石墨晶体层生长形成高度有序的石墨结构。我们的结果提供了蛋白质热转变的机制，并展示了一种潜在策略，即使用无催化剂的水性湿法清洁系统设计用于体内应用的焦蛋白。
