ISDA

Entry Detail

PDB ID:

7DV2

Keywords:

DNA BINDING PROTEIN

Title:

Structure of Sulfolobus solfataricus SegB-DNA complex

Biological Source:

Source Organism:

Saccharolobus solfataricus (strain ATCC 35092 / DSM 1617 / JCM 11322 / P2), synthetic construct

Host Organism:

Escherichia coli

PDB Version:

Deposition Date:

2021-01-12

Release Date:

2021-12-22

Method Details:

Experimental Method:

X-RAY DIFFRACTION

Resolution:

3.10 Å

R-Value Free:

0.27

R-Value Work:

0.22

R-Value Observed:

0.23

Space Group:

C 2 2 21

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Macromolecular Entities

Protein Blast

Polymer Type:polypeptide(L)
Description:SegB
Chain IDs:A, B, C, D
Chain Length:83
Number of Molecules:4
Biological Source:Saccharolobus solfataricus (strain ATCC 35092 / DSM 1617 / JCM 11322 / P2)

UniProt ID:Q981B2

Polymer Type:polydeoxyribonucleotide
Description:DNA (5'-D(P*AP*CP*GP*TP*AP*GP*AP*AP*GP*AP*GP*TP*CP*TP*AP*GP*AP*CP*TP*G)-3')
Chain IDs:E
Chain Length:21
Number of Molecules:1
Biological Source:synthetic construct

Polymer Type:polydeoxyribonucleotide
Description:DNA (5'-D(P*CP*AP*GP*TP*CP*TP*AP*GP*AP*CP*TP*CP*TP*TP*CP*TP*AP*CP*GP*TP*A)-3')
Chain IDs:F
Chain Length:21
Number of Molecules:1
Biological Source:synthetic construct

Ligand Molecules

Primary Citation

Chromosome segregation in Archaea: SegA- and SegB-DNA complex structures provide insights into segrosome assembly.

Yen, C.Y, Lin, M.G, Chen, B.W, Ng, I.W, Read, N, Kabli, A.F, Wu, C.T, Shen, Y.Y, Chen, C.H, Barilla, D, Sun, Y.J, Hsiao, C.D.Show

Nucleic Acids Res. 49 13150 13164 (2021)

PMID: 34850144 DOI: 10.1093/nar/gkab1155

Abstact

Genome segregation is a vital process in all organisms. Chromosome partitioning remains obscure in Archaea, the third domain of life. Here, we investigated the SegAB system from Sulfolobus solfataricus. SegA is a ParA Walker-type ATPase and SegB is a site-specific DNA-binding protein. We determined the structures of both proteins and those of SegA-DNA and SegB-DNA complexes. The SegA structure revealed an atypical, novel non-sandwich dimer that binds DNA either in the presence or in the absence of ATP. The SegB structure disclosed a ribbon-helix-helix motif through which the protein binds DNA site specifically. The association of multiple interacting SegB dimers with the DNA results in a higher order chromatin-like structure. The unstructured SegB N-terminus plays an essential catalytic role in stimulating SegA ATPase activity and an architectural regulatory role in segrosome (SegA-SegB-DNA) formation. Electron microscopy results also provide a compact ring-like segrosome structure related to chromosome organization. These findings contribute a novel mechanistic perspective on archaeal chromosome segregation.

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