Stereo-array isotope labeling (SAIL)

The 20 standard amino acids are labeled such that each CHn group carries at most a single NMR-visible 1H nucleus, the others being replaced by NMR-invisible 2H. The remaining 1H nuclei, shown as lights in the Figure, provide data that allows the NMR structure determination of proteins about twice as large as by conventional NMR approaches. The structure of the 42 kDa maltodextrin-binding protein MBP that is shown in the center of the Figure was solved in collaboration with the laboratory of Prof. Masatsune Kainosho at Tokyo Metropolitan University, Japan, using SAIL in conjunction with the structure calculation program CYANA.

  • Kainosho, M., Torizawa, T., Iwashita, Y., Terauchi, T., Ono, A. M. & Güntert, P. Optimal isotope labeling for NMR protein structure determinations. Nature 440, 52–57 (2006)