Radhakrishnan I, de los Santos C, Patel D J
Department of Biochemistry and Molecular Biophysics, College of Physicians and Surgeons, Columbia University, New York, NY 10032.
J Mol Biol. 1993 Nov 5;234(1):188-97. doi: 10.1006/jmbi.1993.1573.
This study reports on an NMR characterization of an intramolecular purine.purine.pyrimidine (R.RY) triplex containing a central A.AT triple in addition to G.GC and T.AT triples. Our studies establish an A(anti).AT alignment with reversed Hoogsteen pairing stabilized by two N6H ... N hydrogen bonds between adenine residues in the third strand and the purine strand of the duplex. This result, combined with our earlier demonstration of G(anti).GC and T(anti).AT pairing alignments, has provided a definitive experimental approach for differentiating between the base triple pairing possibilities proposed previously by Beal and Dervan for R.RY triplexes.
本研究报告了一种分子内嘌呤-嘌呤-嘧啶（R.RY）三链体的核磁共振表征，该三链体除了含有G.GC和T.AT三联体外，还包含一个中心A.AT三联体。我们的研究确定了一种A（反式）.AT排列，其Hoogsteen配对是反向的，由第三条链中的腺嘌呤残基与双链体嘌呤链之间的两个N6H...N氢键稳定。这一结果，结合我们早期对G（反式）.GC和T（反式）.AT配对排列的证明，为区分Beal和Dervan之前提出的R.RY三链体的碱基三联体配对可能性提供了一种明确的实验方法。
