Institut für Biochemie, Universität Greifswald, Felix-Hausdorff-Str. 4, 17487, Greifswald, Germany.
Angew Chem Int Ed Engl. 2019 Aug 5;58(32):11068-11071. doi: 10.1002/anie.201905372. Epub 2019 Jun 28.
The oligomer d(GCGTG TCAG TG TG ACGC) with short complementary flanking sequences at the 5'- and 3'-ends was shown to fold into three different DNA G-quadruplex species. In contrast, a corresponding oligomer that lacks base complementarity between the two overhang sequences folds into a single parallel G-quadruplex. The three coexisting quadruplex structures were unambiguously identified and structurally characterized through detailed spectral comparisons with well-defined G-quadruplexes formed upon the deliberate incorporation of syn-favoring 8-bromoguanosine analogues into specific positions of the G-core. Two (3+1) hybrid structures coexist with the parallel fold and feature a novel lateral-propeller-propeller loop architecture that has not yet been confirmed experimentally. Both hybrid quadruplexes adopt the same topology and only differ in their pattern of anti→syn transitions and tetrad stackings.
寡聚体 d(GCGTGTCAGTG TGACGC) 具有短的互补侧翼序列在 5'-和 3'-末端，被证明可以折叠成三种不同的 DNA G-四链体物种。相比之下，相应的寡聚体在两个突出序列之间缺乏碱基互补性，折叠成单个平行的 G-四链体。通过与精心设计的将顺式有利的 8-溴鸟嘌呤类似物掺入 G-核心特定位置形成的明确 G-四链体进行详细的光谱比较，明确地鉴定和结构表征了这三种共存的四链体结构。两个 (3+1) 混合结构与平行折叠共存，具有一种新颖的侧向推进器-推进器环结构，尚未通过实验证实。这两种混合四链体采用相同的拓扑结构，仅在反式→顺式转变和四联体堆叠的模式上有所不同。
