A Sequence-Independent Analysis of the Loop Length Dependence of Intramolecular RNA G-Quadruplex Stability and Topology

作者：Zhang Amy Y Q; Bugaut Anthony^*; Balasubramanian Shankar

来源：Biochemistry, 2011, 50(33): 7251-7258.

DOI：10.1021/bi200805j

G-Quadruplexes are noncanonical nucleic acid secondary structures based on guanine association that are readily adopted by G-rich RNA and DNA sequences. Naturally occurring genomic G-quadruplex-forming sequences have functional roles in biology that are mediated through structure. To appreciate how this is achieved, an understanding of the likelihood of G-quadruplex formation and the structural features of the folded species under a defined set of conditions of informative. We previously systematically investigted the thermodynamic stability and folding topology of DNA G-quadruplexes and found a strong dependence of these properties on loop length and loop arrangement [Bugaut, A., and Balasubramanian, S. (2008) Biochemistry 47, 689-697]. Here we report on a complementary analysis of RNA G-quadruplexes using UV melting and circular dichroism spectroscopy that also serves as a comparison to the equivalent DNA G-quadruplex-forming sequences. We found that the thermodynamic stability of G-quadruplex RNA can be modulated by loop length while the overall structure is largely unaffected. The systematic design of our study also revealed subtle loop length dependencies in RNA G-quadruplex structure.

• 出版日期2011-8-23