title: Discovery of widespread GTP-binding motifs in genomic DNA and RNA.
abstract: Biological RNAs that bind small molecules have been implicated in a variety of regulatory and catalytic processes. Inspired by these examples, we used in vitro selection to search a pool of genome-encoded RNA fragments for naturally occurring GTP aptamers. Several aptamer classes were identified, including one (the "G motif") with a G-quadruplex structure. Further analysis revealed that most RNA and DNA G-quadruplexes bind GTP. The G motif is abundant in eukaryotes, and the human genome contains ~75,000 examples with dissociation constants comparable to the GTP concentration of a eukaryotic cell (~300 μM). G-quadruplexes play roles in diverse cellular processes, and our findings raise the possibility that GTP may play a role in the function of these elements. Consistent with this possibility, the sequence requirements of several classes of regulatory G-quadruplexes parallel those of GTP binding.
authors.affiliation: Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA 02138, USA.
authors.forename: Edward A
authors.initials: EA
authors.lastname: Curtis
authors.forename: David R
authors.initials: DR
authors.lastname: Liu
mesh_terms: D000818:Animals; D052157:Aptamers, Nucleotide / Q000378:metabolism; D001483:Base Sequence; D004247:DNA / Q000378:metabolism*; D054856:G-Quadruplexes; D015894:Genome, Human; D006160:Guanosine Triphosphate / Q000378:metabolism*; D006801:Humans; D007700:Kinetics; D011485:Protein Binding; D012313:RNA / Q000378:metabolism*; D016601:RNA-Binding Proteins / Q000378:metabolism
chemical_list: D052157:Aptamers, Nucleotide; D016601:RNA-Binding Proteins; D012313:RNA; D006160:Guanosine Triphosphate; D004247:DNA