Laboratoire de Chimie Physique Moléculaire, École Polytechnique Fédérale de Lausanne , CH-1015 Lausanne, Switzerland.
J Am Chem Soc. 2014 Jul 2;136(26):9288-91. doi: 10.1021/ja5053544. Epub 2014 Jun 24.
The accurate and unambiguous detection of post-translational modifications in proteins and peptides remains a challenging task. We report here the use of cold ion spectroscopy for the identification of phosphorylated tyrosine residues in peptides. This approach employs the wavelength-specific UV fragmentation of cryogenically cooled protonated peptides in the gas phase. In addition to the appearance of specific photofragments, the phosphorylation of tyrosine induces large spectral shifts of the peptide electronic band origins. Quantum chemical calculations and experiments together suggest a certain generality of the use of such shifts in the spectroscopic identification of phosphotyrosines. The enhanced selectivity offered by the joint application of wavelength-specific fragmentation and mass spectrometry of cold molecules can also be used in the identifications of aromatic residues in protonated peptides and, potentially, of other UV-absorbing groups in a variety of large polyatomic ions.
准确而明确地检测蛋白质和肽中的翻译后修饰仍然是一项具有挑战性的任务。我们在这里报告了使用冷离子光谱学来鉴定肽中的磷酸酪氨酸残基。该方法采用在气相中对冷冻质子化肽进行波长特异性的紫外光断裂。除了出现特定的光碎片外，磷酸酪氨酸的存在还会引起肽的电子能带起源的光谱位移。量子化学计算和实验共同表明，在使用这种位移来鉴定磷酸酪氨酸时具有一定的普遍性。通过联合使用波长特异性断裂和冷分子的质谱法，可以提高对质子化肽中芳香族残基的选择性，并且可能在各种大的多原子离子中提高对其他紫外吸收基团的选择性。
