Unusual Topological RNA Architecture with an Eight-Stranded Helical Fragment Containing A‑, G‑, and U‑Tetrads Chao-Da Xiao Takumi Ishizuka Xiao-Qing Zhu Yue Li Hiroshi Sugiyama Yan Xu 10.1021/jacs.6b12274.s001 https://acs.figshare.com/articles/journal_contribution/Unusual_Topological_RNA_Architecture_with_an_Eight-Stranded_Helical_Fragment_Containing_A_G_and_U_Tetrads/4643782 Human telomeric RNA performs various cellular functions such as telomere length regulation, heterochromatin formation, and chromosome end protection. Using a combination of nuclear magnetic resonance, circular dichroism, and gel electrophoresis, we observed an unusual topological structure formed by human telomere RNA r­(GUUAGGGU). Our results showed that every set of four strands formed a parallel G-quadruplex as symmetry-related units containing four G-tetrads, two U-tetrads, and one A-tetrad. An eight-stranded helical fragment containing A-, G-, and U-tetrads provided a central intercalated scaffold that connected two G-quadruplex units in an alternating antiparallel arrangement, giving rise to a novel RNA architecture. This higher order RNA structure is so stable that it would be surprising if similar structures do not occur in nature. Our findings provide a new insight into the behavior of human telomeric RNA molecules. 2017-02-08 00:00:00 chromosome end protection telomere length regulation topological structure gel electrophoresis G-quadruplex units eight-stranded helical fragment heterochromatin formation symmetry-related units Eight-Stranded Helical Fragment Containing RNA molecules order RNA structure antiparallel arrangement novel RNA architecture intercalated scaffold Unusual Topological RNA Architecture