Beijing Normal University, Beijing, 100875, PR China.
J Mass Spectrom. 2013 Jan;48(1):128-34. doi: 10.1002/jms.3136.
Selective cleavage is of great interest in mass spectrometry studies as it can help sequence identification by promoting simple fragmentation pattern of peptides and proteins. In this work, the collision-induced dissociation of peptides containing internal lysine and acetylated lysine residues were studied. The experimental and computational results revealed that multiple fragmentation pathways coexisted when the lysine residue was two amino acid residues away from N-terminal of the peptide. After acetylation of the lysine side-chain, b(n)+ ions were the most abundant primary fragment products and the Lys(Ac)-Gly amide bond became the dominant cleavage site via an oxazolone pathway. Acetylating the side-chain of lysine promoted the selective cleavage of Lys-Xxx amide bond and generated much more information of the peptide backbone sequence. The results re-evaluate the selective cleavage due to the lysine basic side-chain and provide information for studying the post-translational modification of proteins and other bio-molecules containing Lys residues.
选择性裂解在质谱研究中很有意义，因为它可以通过促进肽和蛋白质的简单碎裂模式来帮助序列鉴定。在这项工作中，研究了含有内部赖氨酸和乙酰化赖氨酸残基的肽的碰撞诱导解离。实验和计算结果表明，当赖氨酸残基距离肽的 N 端两个氨基酸残基时，多种碎裂途径共存。赖氨酸侧链乙酰化后，b(n)+离子是最丰富的初级片段产物，通过噁唑啉途径，Lys(Ac)-Gly 酰胺键成为主要的裂解位点。乙酰化赖氨酸侧链促进 Lys-Xxx 酰胺键的选择性裂解，并生成更多肽骨架序列的信息。这些结果重新评估了由于赖氨酸碱性侧链而导致的选择性裂解，并为研究含有赖氨酸残基的蛋白质和其他生物分子的翻译后修饰提供了信息。
