Department of Chemistry, University of California, Berkeley, California, B42 Hildebrand Hall, Berkeley, CA, 94720, USA.
Angew Chem Int Ed Engl. 2017 Jun 26;56(27):7912-7915. doi: 10.1002/anie.201702330. Epub 2017 Jun 5.
Nonvolatile salts are essential for the structures and functions of many proteins and protein complexes but can severely degrade performance of native mass spectrometry by adducting to protein and protein complex ions, thereby reducing sensitivity and mass measuring accuracy. Small nanoelectrospray emitters are used to form protein and protein complex ions directly from high-ionic-strength (>150 mm) nonvolatile buffers with salts that mimic the extracellular environment. Charge-state distributions are not obtained for proteins and protein complexes from six commonly used nonvolatile buffers and ≥150 mm Na with conventionally sized nanoelectrospray emitter tips but are resolved with 0.5 μm tips. This method enables mass measurements of proteins and protein complexes directly from a variety of commonly used buffers with high concentrations of nonvolatile salts and eliminates the need to buffer exchange into volatile ammonium buffers traditionally used in native mass spectrometry.
非挥发性盐对于许多蛋白质和蛋白质复合物的结构和功能至关重要，但它们会通过与蛋白质和蛋白质复合物离子加合，严重降低天然质谱的性能，从而降低灵敏度和质量测量的准确性。小的纳升电喷雾发射器用于直接从模拟细胞外环境的高离子强度（>150 mM）非挥发性缓冲液中形成蛋白质和蛋白质复合物离子。对于通常大小的纳升电喷雾发射器尖端，无法从六种常用的非挥发性缓冲液和≥150 mM Na 获得蛋白质和蛋白质复合物的电荷态分布，但可以使用 0.5 μm 尖端解决。该方法能够直接从各种高浓度非挥发性盐的常用缓冲液中测量蛋白质和蛋白质复合物的质量，并且无需传统上用于天然质谱的缓冲液交换到挥发性氨缓冲液中。
