Structural and thermodynamic characterization of Vibrio fischeri CcdB.

TitleStructural and thermodynamic characterization of Vibrio fischeri CcdB.
Publication TypeJournal Article
Year of Publication2010
AuthorsDe Jonge, N., W. Hohlweg, A. Garcia-Pino, M. Respondek, L. Buts, S. Haesaerts, J. Lah, K. Zangger, and R. Loris
JournalJ Biol Chem
Volume285
Issue8
Pagination5606-13
Date Published2010 Feb 19
Type of Articleta
ISSN1083-351X
KeywordsAliivibrio fischeri, Bacterial Toxins, Hydrophobic and Hydrophilic Interactions, Nuclear Magnetic Resonance, Biomolecular, Protein Multimerization, Protein Structure, Quaternary, Protein Structure, Secondary, Thermodynamics
Abstract

CcdB(Vfi) from Vibrio fischeri is a member of the CcdB family of toxins that poison covalent gyrase-DNA complexes. In solution CcdB(Vfi) is a dimer that unfolds to the corresponding monomeric components in a two-state fashion. In the unfolded state, the monomer retains a partial secondary structure. This observation correlates well with the crystal and NMR structures of the protein, which show a dimer with a hydrophobic core crossing the dimer interface. In contrast to its F plasmid homologue, CcdB(Vfi) possesses a rigid dimer interface, and the apparent relative rotations of the two subunits are due to structural plasticity of the monomer. CcdB(Vfi) shows a number of non-conservative substitutions compared with the F plasmid protein in both the CcdA and the gyrase binding sites. Although variation in the CcdA interaction site likely determines toxin-antitoxin specificity, substitutions in the gyrase-interacting region may have more profound functional implications.

DOI10.1074/jbc.M109.068429
Alternate JournalJ. Biol. Chem.
PubMed ID19959472
PubMed Central IDPMC2820787
Grant ListW 901-B12 / / Austrian Science Fund FWF / Austria