Department of Chemistry, University of Texas at Austin, Austin, Texas 78712, United States.
J Am Soc Mass Spectrom. 2021 Jun 2;32(6):1370-1379. doi: 10.1021/jasms.1c00004. Epub 2021 Mar 8.
Numerous mass spectrometry-based strategies ranging from hydrogen-deuterium exchange to ion mobility to native mass spectrometry have been developed to advance biophysical and structural characterization of protein conformations and determination of protein-ligand interactions. In this study, we focus on the use of ultraviolet photodissociation (UVPD) to examine the structure of human carbonic anhydrase II (hCAII) and its interactions with arylsulfonamide inhibitors. Carbonic anhydrase, which catalyzes the conversion of carbon dioxide to bicarbonate, has been the target of countless thermodynamic and kinetic studies owing to its well-characterized active site, binding cavity, and mechanism of inhibition by hundreds of ligands. Here, we showcase the application of UVPD for evaluating structural changes of hCAII upon ligand binding on the basis of variations in fragmentation of hCAII versus hCAII-arylsulfonamide complexes, particularly focusing on the hydrophobic pocket. To extend the coverage in the midregion of the protein sequence, a supercharging agent was added to the solutions to increase the charge states of the complexes. The three arylsulfonamides examined in this study largely shift the fragmentation patterns in similar ways, despite their differences in binding affinities.
已经开发了许多基于质谱的策略,从氢氘交换到离子淌度到天然质谱,以推进蛋白质构象的生物物理和结构表征以及蛋白质-配体相互作用的测定。在这项研究中,我们专注于使用紫外光解(UVPD)来检查人碳酸酐酶 II(hCAII)的结构及其与芳基磺酰胺抑制剂的相互作用。碳酸酐酶催化二氧化碳转化为碳酸氢盐,由于其特征明显的活性部位、结合腔以及数百种配体的抑制机制,已经成为无数热力学和动力学研究的目标。在这里,我们展示了 UVPD 在评估配体结合时 hCAII 结构变化的应用,其基础是 hCAII 与 hCAII-芳基磺酰胺复合物的碎片变化,特别是关注疏水性口袋。为了扩大蛋白质序列中区域的覆盖范围,在溶液中添加了超荷电试剂以增加复合物的电荷态。尽管这三种芳基磺酰胺的结合亲和力不同,但它们的碎片模式变化方式大致相同。