Chromosome segregation in Archaea: SegA– and SegB–DNA complex structures provide insights into segrosome assembly. Issue 22 (29th November 2021)

• Record Type: Journal Article
• Authors: Yen, Cheng-Yi; Lin, Min-Guan; Chen, Bo-Wei; Ng, Irene W; Read, Nicholas; Kabli, Azhar F; Wu, Che-Ting; Shen, Yo-You; Chen, Chen-Hao; Barillà, Daniela; Sun, Yuh-Ju; Hsiao, Chwan-Deng
• Is Part Of: Nucleic acids research. Volume 49:Issue 22(2021)
• Page Start: 13150
• Page End: 13164
• Publication Date: 2021-11-29
• Subjects: Nucleic acids -- Periodicals; Molecular biology -- Periodicals; 572.805
• DOI: 10.1093/nar/gkab1155
• Languages: English
• ISSNs: 0305-1048

Abstract

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.