Open AccessInteraction of human DNA topoisomerase I with G-quartet structures
Author(s) -
Paola B. Arimondo,
JeanFrançois Riou,
JeanLouis Mergny,
Jamal Tazi,
JianSheng Sun,
Thérèse Garestier,
Claude Hélène
Publication year - 2000
Publication title -
nucleic acids research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 9.008
H-Index - 537
eISSN - 1362-4954
pISSN - 0305-1048
DOI - 10.1093/nar/28.24.4832
Subject(s) - topoisomerase , dna , biology , guanine , hydrogen bond , dna replication , intermolecular force , transcription (linguistics) , stereochemistry , enzyme , dna supercoil , biochemistry , biophysics , gene , molecule , nucleotide , chemistry , linguistics , organic chemistry , philosophy
Because of their role in the control of the topological state of DNA, topoisomerases are ubiquitous and vital enzymes, which participate in nearly all events related to DNA metabolism including replication and transcription. We show here that human topoisomerase I (Topo I) plays an unexpected role of 'molecular matchmaker' for G-quartet formation. G-quadruplexes are multi-stranded structures held together by square planes of four guanines ('G-quartets') interacting by forming Hoogsteen hydrogen bonds. Topo I is able to promote the formation of four-stranded intermolecular DNA structures when added to single-stranded DNA containing a stretch of at least five guanines. We provide evidence that these complexes are parallel G-quartet structures, mediated by tetrads of hydrogen-bonded guanine. In addition, Topo I binds specifically to pre-formed parallel and anti-parallel G4-DNA.
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