Structure of the Cdt1 C-terminal domain: conservation of the winged helix fold in replication licensing factors.
In eukaryotic replication licensing, Cdt1 plays a key role by recruiting the MCM2-7 complex onto the origin of chromosome. The C-terminal domain of mouse Cdt1 (mCdt1C), the most conserved region in Cdt1, is essential for licensing and directly interacts with the MCM2-7 complex. We have determined the structures of mCdt1CS (mCdt1C_small; residues 452 to 557) and mCdt1CL (mCdt1C_large; residues 420 to 557) using X-ray crystallography and solution NMR spectroscopy, respectively. While the N-terminal 31 residues of mCdt1CL form a flexible loop with a short helix near the middle, the rest of mCdt1C folds into a winged helix structure. Together with the middle domain of mouse Cdt1 (mCdt1M, residues 172-368), this study reveals that Cdt1 is formed with a tandem repeat of the winged helix domain. The winged helix fold is also conserved in other licensing factors including archaeal ORC and Cdc6, which supports an idea that these replication initiators may have evolved from a common ancestor. Based on the structure of mCdt1C, in conjunction with the biochemical analysis, we propose a binding site for the MCM complex within the mCdt1C.
Khayrutdinov
Bulat I
BI
The Magnetic Resonance Team, Korea Basic Science Institute, 804-1 Yangchung-Ri, Ochang, Chungbuk 363-883, South Korea.
Bae
Won Jin
WJ
Yun
Young Mi
YM
Lee
Jie Hye
JH
Tsuyama
Takashi
T
Kim
Jung Joo
JJ
Hwang
Eunha
E
Ryu
Kyoung-Seok
KS
Cheong
Hae-Kap
HK
Cheong
Chaejoon
C
Ko
Jung-Soon
JS
Enomoto
Takemi
T
Karplus
P Andrew
PA
Güntert
Peter
P
Tada
Shusuke
S
Jeon
Young Ho
YH
Cho
Yunje
Y
D000595:Amino Acid Sequence; D000818:Animals; D001665:Binding Sites / Q000235:genetics*; D018797:Cell Cycle Proteins / Q000737:chemistry* / Q000235:genetics; D017124:Conserved Sequence / Q000235:genetics*; D004268:DNA-Binding Proteins / Q000737:chemistry* / Q000235:genetics; D051379:Mice; D008969:Molecular Sequence Data; D009154:Mutation; D019906:Nuclear Magnetic Resonance, Biomolecular; D009687:Nuclear Proteins / Q000737:chemistry / Q000235:genetics; D017434:Protein Structure, Tertiary / Q000235:genetics*; D016415:Sequence Alignment
D018797:Cell Cycle Proteins; D004268:DNA-Binding Proteins; D009687:Nuclear Proteins; C498645:Ris2 protein, mouse