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. 2020 Sep 30;2(1):47–76. doi: 10.1039/d0cb00151a

G4-helicases209,212,214,215.

Name Family216,217 Direct-ionality Species Activity (for ligand interaction details, see Section 3c) Associated human disease Ref.
BLM RecQ-like SF2 3′ → 5′ H. sapiens No preferences for a given subclass of G4 (intra- vs. inter-molecular G4, parallel vs. antiparallel G4s); requires 3′-ss overhang for loading; involved in DNA repair via DSB resection and HR; inhibited by G4-ligands (e.g. BRACO19) Bloom syndrome 218–220
Sgs1 RecQ-like SF2 3′ → 5′ S. cerevisiae Orthologue of H. sapiens BLM helicase; inhibited by G4-ligands PIPER — 221 and 222
WRN RecQ-like SF2 3′ → 5′ H. sapiens Wide G4 spectrum; requires 3′-ss overhang for loading; manages replication stress, fork arrest and collapse; inhibited by G4-ligand BRACO19 Werner syndrome 219, 220 and 223
RecQ RecQ-like SF2 3′ → 5′ E. coli Unwinds both intra- and intermolecular G4s; orthologue in H. sapiens is RecQL4; inhibited by G4-ligand NMM 224
DHX36 DEAH, SF2 3′ → 5′ H. sapiens Also known as RHAU (RNA helicase associated with AU-rich element) or G4R1 (G4-resolvase 1); unfolds both DNA and RNA G4s; preference for parallel G4s; inhibited by G4 ligands PDS and PhenDC — 225–227
Pif1 Pif1-like SF1 5′ → 3′ S. cerevisiae Found from yeast to human (hPif1); no preference for a given subclass of G4; requires 5′-ss overhang for loading; inhibited by G4-ligand PhenDC3 — 228–231
RTEL1 DEAH, SF2 5′ → 3′ H. sapiens Involved in genome stability and telomere integrity; unwinds intra- and inter-molecular G4s; inhibited by G4 ligand TMPyP4 Hoyeraal–Hreidarsson syndrome 232 and 233
FANCJ Fe–S, SF2 5′ → 3′ H. sapiens Orthologue of nematode DOG-1 helicase (C. elegans); promotes DNA repair via HR on interaction with BRCA1; resolves telomeric G4; inhibited by G4-ligand telomestatin (TMS) Fanconi anemia 234–236
DDX1 Fe–S (DEAD-box), SF2 5′ → 3′ H. sapiens Unlike FANCJ, DDX1 does not resolve intra- and tetra-molecular G4s (preference for two-stranded G4s); insensitive to TMS treatment Warsaw breakage syndrome 236 and 237
XPD Fe–S (Rad3/XPD), SF2 5′ → 3′ S. acidocaldarius Unlike FANCJ, XPD does not resolve intra- and tetra-molecular G4s; orthologue in H. sapiens is ERCC2; insensitive to TMS treatment Cockayne syndrome (for ERCC2) 236, 238 and 239