Department of Chemistry and Biochemistry, The University of Texas at Austin, 1 University Station A5300, Austin, Texas 78712, USA.
Anal Chem. 2009 Nov 1;81(21):8677-86. doi: 10.1021/ac901554z.
Infrared multiphoton dissociation (IRMPD) was implemented in a novel dual pressure linear ion trap for rapid top-down proteomics. The high pressure cell provided improved trapping and isolation efficiencies while the isotopic profiles of 10+ charged ions could be resolved by mass analysis in the low pressure cell that enabled effective top down protein identification. Striking differences between IRMPD in the low pressure cell and CID in the high pressure cell were observed for proteins ranging from 8.6 to 29 kDa. Because of secondary dissociation, IRMPD yielded product ions in significantly lower charge states as compared to CID, thus facilitating more accurate mass identification and streamlining product ion assignment. This outcome was especially useful for database searching of larger proteins (approximately 29 kDa) as IRMPD substantially improved protein identification and scoring confidence. Also, IRMPD showed an increased selectivity toward backbone cleavages N-terminal to proline and C-terminal to acidic residues (especially for the lowest charge states), which could be useful for a priori spectral predictions and enhanced database searching for protein identification.
红外多光子解离（IRMPD）在新型双压线性离子阱中实现，用于快速自上而下的蛋白质组学。高压池提供了改进的捕获和分离效率，而低压池中的质量分析可以分辨出 10+价带电荷离子的同位素分布，从而实现有效的自上而下的蛋白质鉴定。对于 8.6 至 29 kDa 范围内的蛋白质，在低压池中的 IRMPD 和高压池中的 CID 之间观察到明显的差异。由于次级解离，与 CID 相比，IRMPD 产生的产物离子带电量显著降低，从而更有利于更准确的质量鉴定和简化产物离子分配。对于更大的蛋白质（约 29 kDa）的数据库搜索来说，这一结果尤其有用，因为 IRMPD 极大地提高了蛋白质鉴定和评分的可信度。此外，IRMPD 对脯氨酸 N 端和酸性残基 C 端的肽键裂解具有更高的选择性（特别是在最低电荷状态下），这对于先验光谱预测和增强数据库搜索以进行蛋白质鉴定可能非常有用。
