Chiral recognition between tryptophan (Trp) and carbohydrates such as D-glucose (D-Glc), methyl-α-D-glucoside (D-glucoside), D-maltose, and D-cellobiose in cold gas-phase cluster ions was investigated as a model for chemical evolution in interstellar molecular clouds using a tandem mass spectrometer containing a cold ion trap. The photodissociation mass spectra of cold gas-phase clusters that contained Na+, Trp enantiomers, and D-maltose showed that Na+(D-Glc) was formed via the glycosidic bond cleavage of D-maltose from photoexcited homochiral Na+(D-Trp)(D-maltose), while the dissociation did not occur in heterochiral Na+(L-Trp)(D-maltose). The enantiomer-selective dissociation was also observed in the case of D-cellobiose. The enantiomer-selective glycosidic bond cleavage of disaccharides suggested that photoexcited D-Trp could prevent chemical evolution of sugar chains from D-enantiomer of carbohydrates in molecular clouds. The spectra of gas-phase clusters that contained Na+, Trp enantiomers, and D-Glc indicated that enantiomer-selective protonation of L-Trp from D-Glc could induce enantiomeric excess via collision-activated dissociation of the protonated L-Trp. In the case of protonated clusters, photoexcited H+(L-Trp) dissociated via Cα-Cβ bond cleavage in the presence of D-Glc or D-glucoside, where the excited states of H+(L-Trp) contributed to the enantiomer-selective reaction in the clusters. These enantiomer selectivities in cold gas-phase clusters indicated that chirality of a molecule induced enantiomeric excess of other molecules via enantiomer-selective reactions in molecular clouds.

中文翻译：

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通过光解离探测碳水化合物和色氨酸冷气相簇离子的手性识别。


研究了冷气相簇离子中色氨酸 (Trp) 与 D-葡萄糖 (D-Glc)、甲基-α-D-葡萄糖苷 (D-葡萄糖苷)、D-麦芽糖和 D-纤维二糖等碳水化合物之间的手性识别使用包含冷离子阱的串联质谱仪作为星际分子云中化学演化的模型。含有 Na+、Trp 对映体和 D-麦芽糖的冷气相簇的光解质谱表明，Na+(D-Glc) 是通过 D-麦芽糖从光激发的纯手性 Na+(D-Trp) 中糖苷键断裂而形成的。 D-麦芽糖），而异手性 Na+(L-Trp)(D-麦芽糖) 中未发生解离。在 D-纤维二糖的情况下也观察到对映体选择性解离。二糖的对映体选择性糖苷键断裂表明，光激发的 D-Trp 可以阻止分子云中碳水化合物的 D-对映体的糖链化学演化。含有Na+、Trp对映体和D-Glc的气相簇的光谱表明，D-Glc对L-Trp的对映体选择性质子化可以通过质子化的L-Trp的碰撞激活解离来诱导对映体过量。在质子化簇的情况下，光激发的 H+(L-Trp) 在 D-Glc 或 D-葡萄糖苷存在下通过 Cα-Cβ 键断裂解离，其中 H+(L-Trp) 的激发态有助于对映体选择性团簇中的反应。冷气相簇中的这些对映体选择性表明，分子的手性通过分子云中的对映体选择性反应诱导其他分子的对映体过量。