Solution Structure and Interactions of the Escherichia coli Cell Division Activator Protein CedA,

CedA is a protein that is postulated to be involved in the regulation of cell division in Escherichia coli and related organisms; however, little biological data about its possible mode of action are available. Here we present a three-dimensional structure of this protein as determined by NMR spectroscopy. The protein is made up of four antiparallel β-strands, an α-helix, and a large unstructured stretch of residues at the N-terminus. It shows structural similarity to a family of DNA-binding proteins which interact with dsDNA via a three-stranded β-sheet, suggesting that CedA may be a DNA-binding protein. The putative binding surface of CedA is predominantly positively charged with a number of basic residues surrounding a groove largely dominated by aromatic residues. NMR chemical shift perturbations and gel-shift experiments performed with CedA confirm that the protein binds dsDNA, and its interaction is mediated primarily via the β-sheet.