The monomeric and oligomeric structures of the “FYLLYY” β2 microglobulin (β2m) active sequence, formed in (DMSO/CH3CN) solution, were investigated using electrospray ionization (ESI) mass spectrometry (MS) and tandem mass spectrometry (MS/MS). Dissociation of dimer and trimer ions was investigated by tandem mass spectrometry using collision induced dissociation (CID). The covalent bond fragmentation patterns were observed in the 21+ and 32+ MS/MS spectra (21+ = [dimer+H]1+ and 32+ = [trimer + 2H]2+). A π-π stacking geometry for the FYLLYY 21+ complex and partial parallel β-sheet geometry for the 32+ complex are proposed to be stable structures. The observed covalent bond fragment ions in the MS/MS spectra of the 32+ complex are considered to have originated from the partial parallel β-sheet moiety. The FYLLYY → AALLGY (or FYLLAA) substituted sequence was also investigated by CID-MS/MS. Our MS/MS analysis suggests that the π-π stacking interaction structures are important in dimer binding rather than the structures of a complete parallel or anti-parallel β-sheet 21+ complex.

中文翻译：

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通过碰撞诱导解离和电喷雾电离质谱法分析形成淀粉样蛋白的 FYLLYY 肽的寡聚复合物

使用电喷雾电离 (ESI) 质谱 (MS) 和串联质谱 (MS/MS) 研究了在 (DMSO/CH3CN) 溶液中形成的“FYLLYY”β2 微球蛋白 (β2m) 活性序列的单体和寡聚结构。使用碰撞诱导解离 (CID) 通过串联质谱法研究二聚体和三聚体离子的解离。在 21+ 和 32+ MS/MS 谱图中观察到共价键断裂模式（21+ = [二聚体 + H]1+ 和 32+ = [三聚体 + 2H]2+）。FYLLYY 21+ 复合物的 π-π 堆叠几何结构和 32+ 复合物的部分平行 β-折叠几何结构被认为是稳定的结构。在 32+ 复合物的 MS/MS 谱中观察到的共价键碎片离子被认为源自部分平行的 β-折叠部分。FYLLYY → AALLGY（或 FYLLAA）取代序列也通过 CID-MS/MS 进行了研究。我们的 MS/MS 分析表明 π-π 堆积相互作用结构在二聚体结合中更重要，而不是完全平行或反平行 β-折叠 21+ 复合物的结构。