antiparallel double helix A-form double helix B-form double helix Z-form double helix parallel helix I-motif triple helix quadruplex quadruplex, ONQUADRO-annotated G-quadruplex, G4DSSR-annotated racemic structure only standard nucleotides (A,G,C,T,U,I) … DNATCO Confal Analysis RNA Equiv Class (RNAEQ)-annotated RNACentral-annotated RNACentral R2DT diagrams Rfam-annotated … Aptamer Holliday junction Ribosomal RNA Riboswitch Ribozyme or DNAzyme Transfer RNA Telomere …Enzyme… Polymerase Nuclease Helicase Recombinase Isomerase Lyase Ligase/Synthetase …Regulatory… CRISPR Splicing Gene Silencing Transcription Translation Post-transcriptional Replication/Repair …Structural… Antibody Nucleosome Ribosome Spliceosome Telomere Virus …… DNAproDB analysis 3DFootPrint analysis polymer-like/antibiotic intercalation bis-intercalation minor groove binder major groove binder any 1 2 3 4 ≥5