Selectivity of montmorillonite catalyzed prebiotic reactions of D, L-nucleotides
Selectivity of montmorillonite catalyzed prebiotic reactions of D, L-nucleotides
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蒙脱土催化D、L-核苷酸的益生元反应的选择性
DOI：
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发表时间：
2007
影响因子：
2
通讯作者：
J. Ferris
中科院分区：
文献类型：
--
作者：
P. Joshi;S. Pitsch;J. Ferris
蒙脱土催化D，L-腺苷(D，L-IMPA)的5‘-磷咪唑类化合物的反应(图1a。N=A，R=H)和D，L-尿苷(图1a，N=U，R=H)分别产生长达7 MERS和6 MERS的低聚物。在相同条件下，D-IMPA和D-IMPU的稀溶液反应分别得到长达9和8 MERS的低聚物。这表明D-和L-对映体的同时掺入只能部分抑制齐聚物的形成。对D，L-IMPA形成的二聚体、三聚体和四聚体进行了选择性酶解、与正品比较和质谱分析。如果每一种手性产物的理论量都被形成，那么同种手性产物的存在数量将比预期的更多。对于二聚体(环状和线状)、三聚体和四聚体，均手性产物的比例与每个预期数量的比例分别为1.3、1.6和2.1。在D，L-IMPU反应中，二聚体(环状和线状)、三聚体和四聚体的比例分别为0.8、0.44和1.4，均手性产物不占优势。环状二聚体在D，L-IMPA和D，L-IMPU中所占比例分别为52-66%和44-69%。在没有蒙脱石的情况下，没有形成环状二聚体。D，L-IMPA和D，L-IMPU反应产物的差异可能是由于活化单体结合在蒙脱石催化剂上时取向不同所致。讨论了蒙脱石作为益生菌催化剂选择性的后果。
The montmorillonite-catalyzed reactions of the 5′-phosphorimidazolides of D, L-adenosine (D, L-ImpA) (Figure 1a. N = A, R = H) and D, L-uridine (Figure 1a., N = U, R = H) yields oligomers that were as long as 7 mers and 6 mers, respectively. The reactions of dilute solutions of D-ImpA and D-ImpU under the same conditions gave oligomers as long as 9 and 8 mers respectively. This demonstrated that oligomer formation is only partially inhibited by incorporation of both the D- and L-enantiomers. The structures of the dimers, trimers and tetramer fractions formed from D, L-ImpA was investigated by selective enzymatic hydrolysis, comparison with authentic samples and mass spectrometry. Homochiral products were present in greater amounts than would be expected if theoretical amounts of each were formed. The ratio of the proportion of homochiral products to that of the amount of each expected for the dimers (cyclic and linear), trimers and tetramers, was 1.3, 1.6, and 2.1, respectively. In the D, L-ImpU reaction homochiral products did not predominate with ratios of dimers (cyclic and linear), trimers and tetramers 0.8, 0.44, and 1.4, respectively. The proportions of cyclic dimers in the dimer fraction were 52–66% with D, L-ImpA and 44–69% with D, L-ImpU. No cyclic dimers were formed in the absence of montmorillonite. The differences in the reaction products of D, L-ImpA and D, L-ImpU are likely to be due to the difference in the orientations of the activated monomers when bound to the catalytic sites on montmorillonite. The consequences of the selectivity of montmorillonite as a prebiotic catalyst are discussed.
影响因子：
5.6
作者：
INOUE, T;ORGEL, LE
通讯作者：
ORGEL, LE