Two-repeat human telomeric d(TAGGGTTAGGGT) sequence forms interconverting parallel and antiparallel G-quadruplexes in solution: Distinct topologies, thermodynamic properties, and folding/unfolding kinetics
Two-repeat human telomeric d(TAGGGTTAGGGT) sequence forms interconverting parallel and antiparallel G-quadruplexes in solution: Distinct topologies, thermodynamic properties, and folding/unfolding kinetics
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DOI：
10.1021/ja037616j
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发表时间：
2003-12-10
影响因子：
15
通讯作者：
Patel, DJ
中科院分区：
文献类型：
--
作者：
Phan, AT;Patel, DJ
我们用核磁共振方法证明了两个重复的人端粒序列d(TAGGTTAGGGT)在含K+的溶液中可以形成平行和反平行的G-四链结构。这两种结构都是包含三个堆叠的G-四联体的二聚体G-四链体。序列d(TAGGGUTAGGGT)在第6位含有一个胸腺嘧啶到尿嘧啶的取代，形成一个以平行为主的具有双链反转环的二聚体G-四链体，其结构是对称的，所有的鸟嘌呤都是反的。另一个修饰序列d(UAGGGT(BR)UAGGGT)形成了一个以反平行为主的具有边向环的二聚体G-四链体；其结构是不对称的，含有6个合成鸟嘌呤和6个反鸟嘌呤。这两种结构在溶液中可以共存和相互转化。对于后一种序列，反平行形式在低温下更有利(
We demonstrate by NMR that the two-repeat human telomeric sequence d(TAGGGTTAGGGT) can form both parallel and antiparallel G-quadruplex structures in K+-containing solution. Both structures are dimeric G-quadruplexes involving three stacked G-tetrads. The sequence d(TAGGGUTAGGGT), containing a single thymine-to-uracil substitution at position 6, formed a predominantly parallel dimeric G-quadruplex with double-chain-reversal loops; the structure was symmetric, and all guanines were anti. Another modified sequence, d(UAGGGT(Br)UAGGGT), formed a predominantly antiparallel dimeric G-quadruplex with edgewise loops; the structure was asymmetric with six syn guanines and six anti guanines. The two structures can coexist and interconvert in solution. For the latter sequence, the antiparallel form is more favorable at low temperatures (