Kleinnijenhuis Anne J, Duursma Marc C, Breukink Eefjan, Heeren Ron M A, Heck Albert J R
FOM Institute for Atomic and Molecular Physics (AMOLF), Kruislaan 407, 1098 SJ Amsterdam, The Netherlands.
Anal Chem. 2003 Jul 1;75(13):3219-25. doi: 10.1021/ac0263770.
Electron capture induced dissociation (ECD) and collisionally activated dissociation (CAD) experiments were performed on four lanthionine bridge-containing antibiotics. ECD of lantibiotics produced mainly c and z* ions, as has been observed previously with other peptides, but more interestingly, the less common c* and z ions were observed in abundance in the ECD spectra. These fragments specifically resulted from the cleavage of both a backbone amine bond and the thioether bond in a lanthionine bridge. ECD seemed to induce mainly cleavages near the lanthionine bridges. This fragmentation pattern indicates that lanthionine bridges play a key role in the selectivity of the ECD process. A new mechanism is postulated describing the formation of c* and z ions. Comparative low-energy CAD did not show such specificity. Nondissociative ECD products were quite abundant, suggesting that relatively stable double and triple radicals can be formed in the ECD process. Our results suggest that ECD can be used as a tool to identify the C-terminal attachment site of lanthionine bridges in newly discovered lantibiotics.
对四种含羊毛硫氨酸桥的抗生素进行了电子捕获诱导解离（ECD）和碰撞激活解离（CAD）实验。羊毛硫抗生素的ECD主要产生c离子和z离子，正如之前在其他肽中观察到的那样，但更有趣的是，在ECD光谱中大量观察到了不太常见的c离子和z离子。这些碎片 specifically 是由羊毛硫氨酸桥中的主链胺键和硫醚键断裂产生的。ECD似乎主要诱导羊毛硫氨酸桥附近的裂解。这种裂解模式表明羊毛硫氨酸桥在ECD过程的选择性中起关键作用。提出了一种描述c*离子和z离子形成的新机制。比较低能量的CAD没有显示出这种特异性。非解离ECD产物相当丰富，表明在ECD过程中可以形成相对稳定的双自由基和三自由基。我们的结果表明，ECD可作为一种工具，用于识别新发现的羊毛硫抗生素中羊毛硫氨酸桥的C端连接位点。
