Albany 2013: Book of Abstracts
June 11-15 2013
©Adenine Press (2012)
Incorporation of alternative nucleic acid chemistries into G-quadruplex structure
Nucleic acids that form G-quadruplex (G4) structure have found applications in a host of research and technology regimes. Numerous G4 based aptamer drugs have been identified with pharmacological activity against cancer, HIV, prions, and blood coagulation (Gatto et al. 2009). In the field of nanotechnology, G4 based sensors and nano-machines have also received much attention. The ability to synthesize nucleic acid ex-vivo allows for the site-specific incorporation of non-natural chemistries into nucleic acids that can be used to tune their physical and pharmacological properties. We summarize the results of a series of studies investigating the effective incorporation of alternative nucleic acid chemistries into G4 DNA. These modified chemistries include C8-modified guanine bases, as well as 2'-F, 2'-F-ANA, and Locked nucleic acid (LNA) modifications to the ribose sugar. We report primarily on the effect of these modifications on G-quadruplex folding topology, thermal stability, and structure. The substitution of LNA-guanosine into the core guanine tetrads disrupts structure in specific structural environments. On the other hand, 2’-F- and 2’-F-ANA guanosine can generally be incorporated without disrupting structure when substituted into guanine bases in certain structural conformations. We find that 2’-F-ANA-guanosine and 2’-F-guanosine are powerful tools for controlling the conformation of G4 structures (Lech et al 2011). Functionalization at the C8 of the guanine base stabilizes in a manner dependent on the glycosidic conformation of the base, with different modification chemistries stabilizing to varying extents (Lech et al 2012). The results of these studies provide useful insight on how to effectively incorporate some useful chemical tools from the growing toolbox of modified nucleic acids chemistries into G-quadruplex nucleic acid.
C. J. Lech, Z. Li, B. Heddi, A. T. Phan. (2012) 2’-F-ANA-guanosine and 2’-F-guanosine as powerful tools for structural manipulation of G-quadruplexes.Chemical Communications 48, 11425-11427
C. J. Lech, J. K. C. Lim, J. M. W. Lim, S. Amrane, B. Heddi, A. T. Phan. (2011) Effects of Site-Specific Guanine C8-Modifications on an Tramolecular DNA G-Quadruplex. Biophysical Journal 101, 1987-1998