{
  "abstract": "G-quadruplexes (G4s) make knots in DNA and RNA. One-block G4s can adopt eight different topologies, yet their folding rules are not precisely known. A systematic study of 353 intramolecular G4s enabled us to establish certain characteristics that rule their topology. In the absence of restraints imposed by a ligand or modified guanosines, when two loops are one nucleotide-long (nt), the topology is parallel, regardless of the third loop length. When loops 1 and 3 are 2-nt long, loop 2 length (L 2 ) determines the G4 topology: parallel for L 2 = 1, parallel or antiparallelchair for L 2 = 2, antiparallel-chair for L 2 = 3, and antiparallel-basket for L 2 = 4-5 nts. Diagonal loops require at least 4 nts; the only three structures with a diagonal loop of 3 nts present multiple anomalies. Only three topologies can accommodate a diagonal loop; the other five cannot. This shows the import ance of distinguishing bet ween the eight different topologies. We explain why parallel and hybrid topologies form preferentially three-tetrad G4s, while antiparallel topologies form preferentially two-tetrad G4s. We also explain why bulges between the G4 stem and the hairpin loop in quadruplex-duplex hybrids are sometimes needed. These findings clarify G4 folding principles and topological restraints.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": null,
  "author_total": 2,
  "authors": [
    {
      "name": "Anton Granzhan"
    },
    {
      "name": "Liliane Mouawad"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/1mthn1prhjx98.bib",
  "cited_by": 1,
  "doi": "10.1093/nar/gkag435",
  "fulltext_url": null,
  "id": "1mthn1prhjx98",
  "issns": [
    "0305-1048",
    "1362-4962"
  ],
  "landing_url": "https://hal.science/hal-05857469v1",
  "language": "en",
  "licence": "CC-BY-4.0",
  "licence_label": "CC BY 4.0",
  "licence_source": "article",
  "licence_url": "https://creativecommons.org/licenses/by/4.0/",
  "metadata_licence": null,
  "native_subjects": [
    [
      "hal",
      "0.sdv"
    ],
    [
      "hal",
      "1.sdv.bbm"
    ],
    [
      "hal",
      "2.sdv.bbm.bs"
    ],
    [
      "openalex",
      "1312|DNA and Nucleic Acid Chemistry"
    ]
  ],
  "openalex": "W7161718890",
  "pdf_url": "https://hal.science/hal-05857469/document",
  "pmcid": null,
  "pmid": "42152678",
  "published": "2026-05-19",
  "publisher": "Oxford University Press",
  "ris": "https://research.draconitic.com/paper/1mthn1prhjx98.ris",
  "sources": [
    {
      "first_seen": "2026-11-10T12:20:54Z",
      "native_id": "hal-05857469",
      "source": "hal",
      "url": "https://hal.science/hal-05857469v1"
    }
  ],
  "subjects": [
    {
      "field": "biochemistry",
      "origin": "hal:2.sdv.bbm.bs",
      "subfield": "structural-biology"
    },
    {
      "field": "biology",
      "origin": "hal:0.sdv",
      "subfield": "general"
    }
  ],
  "title": "Topological rules and anomalies in intramolecular G-quadruplex folding: a comprehensive study",
  "title_text": "Topological rules and anomalies in intramolecular G-quadruplex folding: a comprehensive study",
  "type": "peer-reviewed",
  "updated_at": "2026-11-10T12:20:54Z",
  "url": "https://research.draconitic.com/paper/1mthn1prhjx98",
  "venue": "Nucleic Acids Research",
  "versions": []
}