Profusion of G-quadruplexes on both subunits of metazoan ribosomes
(a) BioTASQ binds to human LSU and SSU RNAs in vitro but not to E. coli or T. thermophilus rRNAs. BioTASQ binds G-quadruplex forming fragments of human SSU RNA but not to control RNA (b) Multiple Sequence Alignment of es3 for chordate species. G-tracts are common in chordates, specifically in mammals. Guanines from G-quadruplex forming sequences are highlighted with dark red, all other guanines are pink. All nucleotides are numbered in accordance with H. sapiens 18S rRNA. Human 28S (LSU), 18S (SSU) and E. coli 16S (SSU) rRNAs were extracted from cells. T. thermophilus 23S rRNA was synthesized in vitro. rRNAs were annealed in the presence of potassium and magnesium at pH 7.5, followed by incubation with BioTASQ and streptavidin-coated beads.