Summary information

PDB id
8ht7
Class
DNA binding protein
Method
NMR
Summary
The n-terminal region of cdc6 specifically recognizes human DNA g-quadruplex
Reference
Geng Y, Liu C, Xu N, Shi X, Suen MC, Zhou B, Yan B, Wu C, Li H, Song Y, Chen X, Wang Z, Cai Q, Zhu G (2024): "The N-terminal region of Cdc6 specifically recognizes human DNA G-quadruplex." Int.J.Biol.Macromol., 260, 129487. doi: 10.1016/j.ijbiomac.2024.129487.
Abstract
Guanine (G)-rich nucleic acid sequences can form diverse G-quadruplex structures located in functionally significant genome regions, exerting regulatory control over essential biological processes, including DNA replication in vivo. During the initiation of DNA replication, Cdc6 is recruited by the origin recognition complex (ORC) to target specific chromosomal DNA sequences. This study reveals that human Cdc6 interacts with G-quadruplex structure through a distinct region within the N-terminal intrinsically disordered region (IDR), encompassing residues 7-20. The binding region assumes a hook-type conformation, as elucidated by the NMR solution structure in complex with htel21T18. Significantly, mutagenesis and in vivo investigations confirm the highly specific nature of Cdc6's recognition of G-quadruplex. This research enhances our understanding of the fundamental mechanism governing the interaction between G-quadruplex and the N-terminal IDR region of Cdc6, shedding light on the intricate regulation of DNA replication processes.
G4 notes
3 G-tetrads, 1 G4 helix, 1 G4 stem, 3(+Ln+Lw+Ln), chair(2+2), UDUD

Base-block schematics in six views

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List of 3 G-tetrads

 1 glyco-bond=s-s- sugar=---- groove=wnwn planarity=0.077 type=planar nts=4 GGGG A.DG1,A.DG21,A.DG13,A.DG9
 2 glyco-bond=-s-s sugar=3--3 groove=wnwn planarity=0.041 type=planar nts=4 GGGG A.DG2,A.DG20,A.DG14,A.DG8
 3 glyco-bond=-s-s sugar=3.-3 groove=wnwn planarity=0.218 type=bowl-2 nts=4 GGGG A.DG3,A.DG19,A.DG15,A.DG7

List of 1 G4-helix

In DSSR, a G4-helix is defined by stacking interactions of G-tetrads, regardless of backbone connectivity, and may contain more than one G4-stem.

Helix#1, 3 G-tetrad layers, INTRA-molecular, with 1 stem

 1  glyco-bond=s-s- sugar=---- groove=wnwn Major-->WC nts=4 GGGG A.DG1,A.DG21,A.DG13,A.DG9
 2  glyco-bond=-s-s sugar=3--3 groove=wnwn WC-->Major nts=4 GGGG A.DG2,A.DG20,A.DG14,A.DG8
 3  glyco-bond=-s-s sugar=3.-3 groove=wnwn WC-->Major nts=4 GGGG A.DG3,A.DG19,A.DG15,A.DG7
  step#1  mm(<>,outward)  area=9.53  rise=3.26 twist=23.2
  step#2  pm(>>,forward)  area=16.65 rise=3.76 twist=22.4
  strand#1 DNA glyco-bond=s-- sugar=-33 nts=3 GGG A.DG1,A.DG2,A.DG3
  strand#2 DNA glyco-bond=-ss sugar=--. nts=3 GGG A.DG21,A.DG20,A.DG19
  strand#3 DNA glyco-bond=s-- sugar=--- nts=3 GGG A.DG13,A.DG14,A.DG15
  strand#4 DNA glyco-bond=-ss sugar=-33 nts=3 GGG A.DG9,A.DG8,A.DG7

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2 stacking diagrams
 1  glyco-bond=s-s- sugar=---- groove=wnwn Major-->WC nts=4 GGGG A.DG1,A.DG21,A.DG13,A.DG9
2 glyco-bond=-s-s sugar=3--3 groove=wnwn WC-->Major nts=4 GGGG A.DG2,A.DG20,A.DG14,A.DG8
step#1 mm(<>,outward) area=9.53 rise=3.26 twist=23.2

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 2  glyco-bond=-s-s sugar=3--3 groove=wnwn WC-->Major nts=4 GGGG A.DG2,A.DG20,A.DG14,A.DG8
3 glyco-bond=-s-s sugar=3.-3 groove=wnwn WC-->Major nts=4 GGGG A.DG3,A.DG19,A.DG15,A.DG7
step#2 pm(>>,forward) area=16.65 rise=3.76 twist=22.4

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List of 1 G4-stem

In DSSR, a G4-stem is defined as a G4-helix with backbone connectivity. Bulges are also allowed along each of the four strands.

Stem#1, 3 G-tetrad layers, 3 loops, INTRA-molecular, UDUD, anti-parallel, 3(+Ln+Lw+Ln), chair(2+2)

 1  glyco-bond=s-s- sugar=---- groove=wnwn Major-->WC nts=4 GGGG A.DG1,A.DG21,A.DG13,A.DG9
 2  glyco-bond=-s-s sugar=3--3 groove=wnwn WC-->Major nts=4 GGGG A.DG2,A.DG20,A.DG14,A.DG8
 3  glyco-bond=-s-s sugar=3.-3 groove=wnwn WC-->Major nts=4 GGGG A.DG3,A.DG19,A.DG15,A.DG7
  step#1  mm(<>,outward)  area=9.53  rise=3.26 twist=23.2
  step#2  pm(>>,forward)  area=16.65 rise=3.76 twist=22.4
  strand#1  U DNA glyco-bond=s-- sugar=-33 nts=3 GGG A.DG1,A.DG2,A.DG3
  strand#2  D DNA glyco-bond=-ss sugar=--. nts=3 GGG A.DG21,A.DG20,A.DG19
  strand#3  U DNA glyco-bond=s-- sugar=--- nts=3 GGG A.DG13,A.DG14,A.DG15
  strand#4  D DNA glyco-bond=-ss sugar=-33 nts=3 GGG A.DG9,A.DG8,A.DG7
  loop#1 type=lateral   strands=[#1,#4] nts=3 TTA A.DT4,A.DT5,A.DA6
  loop#2 type=lateral   strands=[#4,#3] nts=3 TTA A.DT10,A.DT11,A.DA12
  loop#3 type=lateral   strands=[#3,#2] nts=3 TTT A.DT16,A.DT17,A.DT18

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