3EZ6

Structure of parA-ADP complex:tetragonal form

Summary for 3EZ6

• Entry DOI: 10.2210/pdb3ez6/pdb
• Related: 3EZ2 3EZ7 3EZ9 3EZF
• Descriptor: Plasmid partition protein A, ADENOSINE-5'-DIPHOSPHATE, MAGNESIUM ION, ... (4 entities in total)
• Functional Keywords: partition, dna binding, winged-hth, segregation, plasmid, plasmid partition, dna binding protein
• Biological source: Escherichia coli
• Total number of polymer chains: 2
• Total formula weight: 89550.05

Authors

Schumacher, M.A. (deposition date: 2008-10-22, release date: 2009-06-02, Last modification date: 2023-09-06)

Primary citation

Dunham, T.D.,Xu, W.,Funnell, B.E.,Schumacher, M.A.
Structural basis for ADP-mediated transcriptional regulation by P1 and P7 ParA.
Embo J., 28:1792-1802, 2009

PubMed Abstract: The accurate segregation of DNA is essential for the faithful inheritance of genetic information. Segregation of the prototypical P1 plasmid par system requires two proteins, ParA and ParB, and a centromere. When bound to ATP, ParA mediates segregation by interacting with centromere-bound ParB, but when bound to ADP, ParA fulfils a different function: DNA-binding transcription autoregulation. The structure of ParA is unknown as is how distinct nucleotides arbitrate its different functions. To address these questions, we carried out structural and biochemical studies. Crystal structures show that ParA consists of an elongated N-terminal alpha-helix, which unexpectedly mediates dimerization, a winged-HTH and a Walker-box containing C-domain. Biochemical data confirm that apoParA forms dimers at physiological concentrations. Comparisons of four apoParA structures reveal a strikingly flexible dimer interface that allows ParA to adopt multiple conformations. The ParA-ADP structure shows that ADP-binding activates DNA binding using a bipartite mechanism. First, it locks in one specific dimer conformation, and second, it induces the folding of two DNA-binding basic motifs that we show are critical for operator binding.

PubMed: 19461582
DOI: 10.1038/emboj.2009.120

Experimental method

X-RAY DIFFRACTION (2.58 Å)