Department of Chemistry University of Texas at Austin Austin , Texas 78712 , United States.
Thermo Fisher Scientific , 28199 Bremen , Germany.
Anal Chem. 2018 May 1;90(9):5896-5902. doi: 10.1021/acs.analchem.8b00724. Epub 2018 Apr 18.
We demonstrate a method for determining the collision cross-sections (CCSs) of protein ions based on the decay rate of the time-domain transient signal from an Orbitrap mass analyzer. Multiply charged ions of ubiquitin, cytochrome c, and myoglobin were generated by electrospray ionization of both denaturing solutions and ones with high salt content to preserve native-like structures. A linear relationship between the pressure in the Orbitrap analyzer and the transient decay rate was established and used to demonstrate that the signal decay is primarily due to ion-neutral collisions for protein ions across the entire working pressure range of the instrument. The CCSs measured in this study were compared with previously published CCS values measured by ion mobility mass spectrometry (IMS), and results from the two methods were found to differ by less than 7% for all charge states known to adopt single gas-phase conformations.
我们展示了一种基于轨道阱质谱仪的时域瞬态信号衰减率来确定蛋白质离子碰撞截面（CCS）的方法。通过对变性溶液和高盐含量溶液进行电喷雾电离，产生了泛素、细胞色素 c 和肌红蛋白的多电荷离子，以保持类似天然的结构。在轨道阱分析仪中的压力和瞬态衰减率之间建立了线性关系，并利用该关系证明了信号衰减主要是由于蛋白质离子在仪器的整个工作压力范围内与中性分子的碰撞。本研究中测量的 CCS 值与先前通过离子淌度质谱法（IMS）测量的 CCS 值进行了比较，对于已知采用单一气相构象的所有电荷状态，两种方法的结果差异小于 7%。
