Electrospray mass spectrometry of telomeric RNA (TERRA) reveals the formation of stable multimeric G-quadruplex structures.
We report on the self-assembled structures formed by 12-mer, 22-mer, and 45-mer telomeric RNA (telRNA/TERRA) sequences compared to their DNA analogues, as studied by electrospray mass spectrometry, circular dichroism, and thermal denaturation. The major difference between telomeric RNA and DNA sequences is the ability of telomeric RNA to form higher-order dimeric assemblies, initiated by cation-mediated stacking of two parallel G-quadruplex subunits. The 5'-5' stacking had been observed recently by NMR for the r(GGGUUAGGGU) 10-mer (Martadinata, H.; Phan, A. T. J. Am. Chem. Soc. 2009, 131, 2570); the present work shows that stacking also occurs for the 22-mer containing four G-tracts and for the 45-mer containing eight G-tracts, suggesting a general structural feature of telomeric RNA. The importance of kinetic effects in multimer formation, unfolding, and structural rearrangements is also highlighted.
Collie
Gavin W
GW
CRUK Biomolecular Structure Group, The School of Pharmacy, University of London, WC1N 1AX London, United Kingdom.
Parkinson
Gary N
GN
Neidle
Stephen
S
Rosu
Frédéric
F
De Pauw
Edwin
E
Gabelica
Valérie
V
D001483:Base Sequence; D004247:DNA; D054856:G-Quadruplexes; D009690:Nucleic Acid Conformation; D012313:RNA / Q000737:chemistry*; D020871:RNA Stability; D021241:Spectrometry, Mass, Electrospray Ionization; D016615:Telomere / Q000235:genetics*
D012313:RNA; D004247:DNA