Abstract: Silk fibers are widely used because of their strong mechanical performance and good biocompatibility. People have tried to understand the natural spinning mechanism of silkworm, the relationship between the structure and the function of silk fibroin, and the factors affecting the secondary structure transition of silk fibroin. Among the methods being used to study silk fibroin, the most effective one is magnetic resonance spectroscopy, including both nuclear magnetic resonance (NMR) and electron paramagnetic resonance (EPR). We have used NMR techniques to study the conformation of silk fibroin and how it is affected by environmental factors such as pH and metal ions (K⁺, Na⁺, Ca²⁺, Cu²⁺ and Zn²⁺) etc. We have also applied EPR spectroscopy to investigate the interaction between Cu(Ⅱ) and silk fibroin in order to discover the intrinsic relationship between conformational transition of silk fibroin and its interaction with Cu(Ⅱ). Besides, a generalized two-dimensional NMR correlation spectroscopy method has been developed for efficiently reducing the traditional 2D NMR experimental time. In this paper, the related work in our group during the past few years is reviewed.

Key words: NMR, silk fibroin, review, EPR, generalized two-dimensional correlation, conformation