1. Chromosome segregation in Archaea: SegA- and SegB-DNA complex structures provide insights into segrosome assembly.
- Author
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Yen CY, Lin MG, Chen BW, Ng IW, Read N, Kabli AF, Wu CT, Shen YY, Chen CH, Barillà D, Sun YJ, and Hsiao CD
- Subjects
- Adenosine Diphosphate metabolism, Adenosine Triphosphatases chemistry, Adenosine Triphosphatases genetics, Adenosine Triphosphatases metabolism, Adenosine Triphosphate metabolism, Archaeal Proteins chemistry, Archaeal Proteins metabolism, Chromatin genetics, Chromatin metabolism, Chromatin ultrastructure, Crystallography, X-Ray, DNA, Archaeal chemistry, DNA, Archaeal metabolism, DNA-Binding Proteins chemistry, DNA-Binding Proteins genetics, DNA-Binding Proteins metabolism, Microscopy, Electron, Models, Molecular, Multiprotein Complexes chemistry, Multiprotein Complexes metabolism, Multiprotein Complexes ultrastructure, Mutation, Nucleic Acid Conformation, Protein Binding, Protein Conformation, Sulfolobus solfataricus metabolism, Archaeal Proteins genetics, Chromosome Segregation, Chromosomes, Archaeal genetics, DNA, Archaeal genetics, Sulfolobus solfataricus genetics
- 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., (© The Author(s) 2021. Published by Oxford University Press on behalf of Nucleic Acids Research.)
- Published
- 2021
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