title: Order and disorder in the domain organization of the plasmid partition protein KorB.
abstract: The plasmid partition protein KorB has a dual role: it is essential for the correct segregation of the low copy number broad host range RK2 plasmid while also being an important regulator of transcription. KorB belongs to the ParB family of proteins, and partitioning in RK2 has been studied as a simplified model of bacterial chromosome segregation. Structural information on full-length ParB proteins is limited, mainly due to the inability to grow crystals suitable for diffraction studies. We show, using CD and NMR, that KorB has regions of significant intrinsic disorder and hence it adopts a multiplicity of conformations in solution. The biophysical data are consistent with bioinformatic predictions based on the amino acid sequence that the N-terminal region and also the region between the central DNA-binding domain and the C-terminal dimerization domain are intrinsically disordered. We have used small angle x-ray scattering data to determine the ensemble of solution conformations for KorB and selected deletion mutants, based on models of the known domain structures. This conformational range of KorB is likely to be biologically required for DNA partitioning and for binding to a diverse set of partner proteins.
authors.affiliation: School of Biosciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, United Kingdom.
authors.forename: Karthik
authors.initials: K
authors.lastname: Rajasekar
authors.affiliation: School of Biosciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, United Kingdom.
authors.forename: Sidra Tul
authors.initials: ST
authors.lastname: Muntaha
authors.affiliation: Protein Design Laboratory, Yokohama City University, 1-7-29, Suehiro-cho, Tsurumi-ku, Yokohama, Kanagawa 230-0045, Japan.
authors.forename: Jeremy R H
authors.initials: JRH
authors.lastname: Tame
authors.affiliation: School of Biosciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, United Kingdom.
authors.forename: Sireesha
authors.initials: S
authors.lastname: Kommareddy
authors.affiliation: National Centre for Macromolecular Hydrodynamics, School of Biosciences, Sutton Bonington Campus, University of Nottingham, Leicestershire LE12 5RD, United Kingdom.
authors.forename: Gordon
authors.initials: G
authors.lastname: Morris
authors.affiliation: School of Biosciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, United Kingdom.
authors.forename: Christopher W
authors.initials: CW
authors.lastname: Wharton
authors.affiliation: School of Biosciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, United Kingdom.
authors.forename: Christopher M
authors.initials: CM
authors.lastname: Thomas
authors.affiliation: School of Biosciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, United Kingdom.
authors.forename: Scott A
authors.initials: SA
authors.lastname: White
authors.affiliation: School of Biosciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, United Kingdom. Electronic address: e.i.hyde@bham.ac.uk.
authors.forename: Eva I
authors.initials: EI
authors.lastname: Hyde
authors.affiliation: National Centre for Macromolecular Hydrodynamics, School of Biosciences, Sutton Bonington Campus, University of Nottingham, Leicestershire LE12 5RD, United Kingdom. Electronic address: dj.scott@nottingham.ac.uk.
authors.forename: David J
authors.initials: DJ
authors.lastname: Scott
mesh_terms: D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000737:chemistry*; D002942:Circular Dichroism; D008969:Molecular Sequence Data; D019906:Nuclear Magnetic Resonance, Biomolecular; D010957:Plasmids; D011487:Protein Conformation; D017386:Sequence Homology, Amino Acid
chemical_list: D001426:Bacterial Proteins; C053863:KorB protein, Plasmid RK2