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Propeller-type parallel-stranded G-quadruplexes in the human c-myc promoter.

ABSTRACT: The nuclease-hypersensitivity element III1 in the c-myc promoter is a good anticancer target since it largely controls transcriptional activation of the important c-myc oncogene. Recently, the guanine-rich strand of this element has been shown to form an equilibrium between G-quadruplex structures built from two different sets of G-stretches; two models of intramolecular fold-back antiparallel-stranded G-quadruplexes, called "basket" and "chair" forms, were proposed. Here, we show by NMR that two sequences containing these two sets of G-stretches form intramolecular propeller-type parallel-stranded G-quadruplexes in K(+)-containing solution. The two structures involve a core of three stacked G-tetrads formed by four parallel G-stretches with all anti guanines and three double-chain-reversal loops bridging three G-tetrad layers. The central loop contains two or six residues, while the two other loops contain only one residue.

SUBMITTER: Phan AT

PROVIDER: S-EPMC4692381 | biostudies-literature | 2004 Jul

REPOSITORIES: biostudies-literature

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Propeller-type parallel-stranded G-quadruplexes in the human c-myc promoter.

Phan Anh Tuân AT Modi Yasha S YS Patel Dinshaw J DJ

Journal of the American Chemical Society 20040701 28

The nuclease-hypersensitivity element III1 in the c-myc promoter is a good anticancer target since it largely controls transcriptional activation of the important c-myc oncogene. Recently, the guanine-rich strand of this element has been shown to form an equilibrium between G-quadruplex structures built from two different sets of G-stretches; two models of intramolecular fold-back antiparallel-stranded G-quadruplexes, called "basket" and "chair" forms, were proposed. Here, we show by NMR that tw ...[more]

PMID: 15250723

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