Order and disorder in the domain organization of the plasmid partition protein KorB.
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.
Rajasekar
Karthik
K
School of Biosciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, United Kingdom.
Muntaha
Sidra Tul
ST
School of Biosciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, United Kingdom.
Tame
Jeremy R H
JRH
Protein Design Laboratory, Yokohama City University, 1-7-29, Suehiro-cho, Tsurumi-ku, Yokohama, Kanagawa 230-0045, Japan.
Kommareddy
Sireesha
S
School of Biosciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, United Kingdom.
Morris
Gordon
G
National Centre for Macromolecular Hydrodynamics, School of Biosciences, Sutton Bonington Campus, University of Nottingham, Leicestershire LE12 5RD, United Kingdom.
Wharton
Christopher W
CW
School of Biosciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, United Kingdom.
Thomas
Christopher M
CM
School of Biosciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, United Kingdom.
White
Scott A
SA
School of Biosciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, United Kingdom.
Hyde
Eva I
EI
School of Biosciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, United Kingdom. Electronic address: e.i.hyde@bham.ac.uk.
Scott
David J
DJ
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.
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
D001426:Bacterial Proteins; C053863:KorB protein, Plasmid RK2