Neuhaus D, Wagner G, Vasák M, Kägi J H, Wüthrich K
Eur J Biochem. 1984 Sep 17;143(3):659-67. doi: 10.1111/j.1432-1033.1984.tb08419.x.
Heteronuclear spin-spin couplings between 113Cd and C beta protons of the metal-bound cysteines were observed in phase-sensitive, double-quantum filtered, homonuclear two-dimensional correlated (COSY) 1H NMR spectra of 113Cd-metallothionein-2 from rabbit liver. Comparison of 113Cd- and 112Cd-metallothionein-2 spectra revealed that 19 1H spin systems show heteronuclear couplings to at least one 113Cd and were thus identified as 19 of the 20 cysteines in this protein. From a detailed analysis of the manifestations of heteronuclear couplings in the homonuclear 1H COSY spectra, two cysteines could be identified as 'bridging cysteines', with spin-spin couplings to two different 113Cd nuclei. The observed 113Cd-1H coupling constants vary between less than or equal to 5 Hz and 80 Hz.
在兔肝来源的113Cd-金属硫蛋白-2的相敏、双量子滤波、同核二维相关（COSY）1H NMR谱中，观察到金属结合半胱氨酸的113Cd与Cβ质子之间的异核自旋-自旋耦合。对113Cd-和112Cd-金属硫蛋白-2谱的比较表明，19个1H自旋系统显示出与至少一个113Cd的异核耦合，因此被确定为该蛋白20个半胱氨酸中的19个。通过对同核1H COSY谱中异核耦合表现的详细分析，可将两个半胱氨酸鉴定为“桥连半胱氨酸”，它们与两个不同的113Cd核存在自旋-自旋耦合。观察到的113Cd-1H耦合常数在小于或等于5 Hz至80 Hz之间变化。
