ParA2, a Vibrio cholerae chromosome partitioning protein, forms left-handed helical filaments on DNA.

Détails

ID Serval
serval:BIB_6FAEA31F23C9
Type
Article: article d'un périodique ou d'un magazine.
Collection
Publications
Institution
Titre
ParA2, a Vibrio cholerae chromosome partitioning protein, forms left-handed helical filaments on DNA.
Périodique
Proceedings of the National Academy of Sciences of the United States of America
Auteur(s)
Hui M.P., Galkin V.E., Yu X., Stasiak A.Z., Stasiak A., Waldor M.K., Egelman E.H.
ISSN
1091-6490[electronic], 0027-8424[linking]
Statut éditorial
Publié
Date de publication
2010
Volume
107
Numéro
10
Pages
4590-4595
Langue
anglais
Résumé
Most bacterial chromosomes contain homologs of plasmid partitioning (par) loci. These loci encode ATPases called ParA that are thought to contribute to the mechanical force required for chromosome and plasmid segregation. In Vibrio cholerae, the chromosome II (chrII) par locus is essential for chrII segregation. Here, we found that purified ParA2 had ATPase activities comparable to other ParA homologs, but, unlike many other ParA homologs, did not form high molecular weight complexes in the presence of ATP alone. Instead, formation of high molecular weight ParA2 polymers required DNA. Electron microscopy and three-dimensional reconstruction revealed that ParA2 formed bipolar helical filaments on double-stranded DNA in a sequence-independent manner. These filaments had a distinct change in pitch when ParA2 was polymerized in the presence of ATP versus in the absence of a nucleotide cofactor. Fitting a crystal structure of a ParA protein into our filament reconstruction showed how a dimer of ParA2 binds the DNA. The filaments formed with ATP are left-handed, but surprisingly these filaments exert no topological changes on the right-handed B-DNA to which they are bound. The stoichiometry of binding is one dimer for every eight base pairs, and this determines the geometry of the ParA2 filaments with 4.4 dimers per 120 A pitch left-handed turn. Our findings will be critical for understanding how ParA proteins function in plasmid and chromosome segregation.
Mots-clé
Adenosine Diphosphate/chemistry, Adenosine Diphosphate/metabolism, Adenosine Triphosphatases/chemistry, Adenosine Triphosphatases/metabolism, Adenosine Triphosphate/chemistry, Adenosine Triphosphate/metabolism, Bacterial Proteins/chemistry, Bacterial Proteins/metabolism, Chromosomes, Bacterial/genetics, DNA/chemistry, DNA/metabolism, DNA-Binding Proteins/chemistry, DNA-Binding Proteins/metabolism, Hydrolysis, Kinetics, Microscopy, Electron, Models, Molecular, Plasmids/genetics, Protein Binding, Protein Multimerization, Protein Structure, Secondary, Protein Structure, Tertiary, Vibrio cholerae/genetics, Vibrio cholerae/metabolism
Pubmed
Web of science
Open Access
Oui
Création de la notice
26/11/2010 12:27
Dernière modification de la notice
20/08/2019 15:28
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