Chromosome segregation in Archaea: SegA- and SegB-DNA complex structures provide insights into segrosome assembly.
Nucleic Acids Res
; 49(22): 13150-13164, 2021 12 16.
Article
in En
| MEDLINE
| ID: mdl-34850144
ABSTRACT
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.
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Archaeal Proteins
/
DNA, Archaeal
/
Chromosomes, Archaeal
/
Chromosome Segregation
/
Sulfolobus solfataricus
Type of study:
Prognostic_studies
Language:
En
Journal:
Nucleic Acids Res
Year:
2021
Type:
Article
Affiliation country:
Taiwan