A chemometric approach to detection and characterization of multiple protein conformers in solution using electrospray ionization mass spectrometry
A chemometric approach to detection and characterization of multiple protein conformers in solution using electrospray ionization mass spectrometry
复制标题
DOI：
10.1021/ac034095
复制
发表时间：
2003-08-15
影响因子：
7.4
通讯作者：
Kaltashov, IA
中科院分区：
文献类型：
--
作者：
Mohimen, A;Dobo, A;Kaltashov, IA
电喷雾电离质谱中的蛋白质离子电荷态分布有可能提供丰富的蛋白质动力学信息，因为它们包含溶液中所有蛋白质构象的贡献。这种离子贡献经常重叠，限制了可以从光谱中提取的有用信息的量。在本工作中，通过使用化学计量学方法克服了这一困难，该方法允许进行光谱去卷积并提取关于单个蛋白质构象异构体的信息。通过在一系列接近天然和变性条件下获得一系列光谱来进行实验，以确保构象异构体群体的显著变化。在实验过程中取样的蛋白质构象异构体的总数通过使收集的光谱的集合经受奇异值分解来确定。然后使用监督优化程序确定每个构象异构体对总信号的离子贡献。该方法的验证已经进行了监测酸和酒精诱导的平衡状态的良好特征的模型蛋白质，胰凝乳蛋白酶抑制剂2（两个国家），泛素（三个国家）和脱辅基肌红蛋白（四个国家）。对于每一个模型蛋白质，一个新的化学计量程序产生了一个蛋白质动力学的图片，是在良好的协议与他们的记录行为（与其他生物物理工具研究）。新的方法似乎是非常适合于监测蛋白质动力学在高度异质性系统组成的多个蛋白质采样的构象状态范围。
Protein ion charge state distributions in electrospray ionization mass spectra have a potential to provide a wealth of information on protein dynamics, because they contain contributions from all protein conformers present in solution. Such ionic contributions often overlap, limiting the amount of useful information that can be extracted from the spectra. This difficulty is overcome in the present work by using a chemometric approach, which allows spectral deconvolution to be carried out and information on individual protein conformers to be extracted. Experiments are carried out by acquiring a series of spectra over a range of near-native and denaturing conditions to ensure significant changes in the conformers' populations. A total number of protein conformers sampled in the course of the experiments is determined by subjecting the set of collected spectra to singular value decomposition. Ionic contributions of each conformer to the total signal are then determined using a supervised optimization routine. Validation of the method has been carried out by monitoring acid- and alcohol-induced equilibrium states of well-characterized model proteins, chymotrypsin inhibitor 2 (two states), ubiquitin (three states) and apo-myoglobin (four states). For each of the model proteins, a new chemometric procedure yielded a picture of protein dynamics that was in excellent agreement with their documented behavior (as studied with other biophysical tools). The new method appears to be well-suited for monitoring protein dynamics in highly heterogeneous systems consisting of multiple proteins sampling a range of conformational states.