Departments of Chemical and Biological Engineering, Chemistry, and Molecular Biosciences, the Chemistry of Life Processes Institute, and the Proteomics Center of Excellence, Northwestern University, Evanston, Illinois 60208, United States.
Thermo Fisher Scientific, San Jose, California 95134, United States.
Anal Chem. 2021 Feb 9;93(5):2723-2727. doi: 10.1021/acs.analchem.0c03282. Epub 2020 Dec 15.
Native mass spectrometry involves transferring large biomolecular complexes into the gas phase, enabling the characterization of their composition and stoichiometry. However, the overlap in distributions created by residual solvation, ionic adducts, and post-translational modifications creates a high degree of complexity that typically goes unresolved at masses above ∼150 kDa. Therefore, native mass spectrometry would greatly benefit from higher resolution approaches for intact proteins and their complexes. By recording mass spectra of individual ions via charge detection mass spectrometry, we report isotopic resolution for pyruvate kinase (232 kDa) and β-galactosidase (466 kDa), extending the limits of isotopic resolution for high mass and high / by >2.5-fold and >1.6-fold, respectively.
天然质谱涉及将大生物分子复合物转移到气相中，从而能够对其组成和化学计量进行表征。然而，残留溶剂化、离子加合物和翻译后修饰所产生的分布重叠，使得在质量超过约 150 kDa 时，会产生高度复杂的情况，通常无法解决。因此，天然质谱非常需要更高分辨率的方法来分析完整的蛋白质及其复合物。通过电荷检测质谱法记录单个离子的质谱，我们报告了丙酮酸激酶（232 kDa）和β-半乳糖苷酶（466 kDa）的同位素分辨率，分别将高质量和高分辨率的同位素分辨率提高了>2.5 倍和>1.6 倍。
