title: DNA recognition by Escherichia coli CbpA protein requires a conserved arginine-minor-groove interaction.
abstract: Curved DNA binding protein A (CbpA) is a co-chaperone and nucleoid associated DNA binding protein conserved in most γ-proteobacteria. Best studied in Escherichia coli, CbpA accumulates to >2500 copies per cell during periods of starvation and forms aggregates with DNA. However, the molecular basis for DNA binding is unknown; CbpA lacks motifs found in other bacterial DNA binding proteins. Here, we have used a combination of genetics and biochemistry to elucidate the mechanism of DNA recognition by CbpA. We show that CbpA interacts with the DNA minor groove. This interaction requires a highly conserved arginine side chain. Substitution of this residue, R116, with alanine, specifically disrupts DNA binding by CbpA, and its homologues from other bacteria, whilst not affecting other CbpA activities. The intracellular distribution of CbpA alters dramatically when DNA binding is negated. Hence, we provide a direct link between DNA binding and the behaviour of CbpA in cells.
authors: Institute of Microbiology and Infection, School of Biosciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK.
authors: Kiran
authors: K
authors: Chintakayala
authors: Institute of Microbiology and Infection, School of Biosciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK.
authors: Laura E
authors: LE
authors: Sellars
authors: Institute of Microbiology and Infection, School of Biosciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK.
authors: Shivani S
authors: SS
authors: Singh
authors: Leiden Institute of Chemistry, Gorlaeus Laboratories, Leiden University, Leiden, The Netherlands.
authors: Rajesh
authors: R
authors: Shahapure
authors: Department of Bionanoscience, Kavli Institute of Nanoscience, Delft University of Technology, Delft, The Netherlands.
authors: Ilja
authors: I
authors: Westerlaken
authors: Department of Bionanoscience, Kavli Institute of Nanoscience, Delft University of Technology, Delft, The Netherlands.
authors: Anne S
authors: AS
authors: Meyer
authors: Leiden Institute of Chemistry, Gorlaeus Laboratories, Leiden University, Leiden, The Netherlands.
authors: Remus T
authors: RT
authors: Dame
authors: Institute of Microbiology and Infection, School of Biosciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK d.grainger@bham.ac.uk.
authors: David C
authors: DC
authors: Grainger
mesh_terms: D019943:Amino Acid Substitution; D001120:Arginine / Q000737:chemistry*; D002352:Carrier Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D004247:DNA / Q000737:chemistry / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D029968:Escherichia coli Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D008958:Models, Molecular; D009690:Nucleic Acid Conformation; D011485:Protein Binding; D055503:Protein Multimerization
chemical_list: D002352:Carrier Proteins; C492508:CbpM protein, E coli; D004268:DNA-Binding Proteins; D029968:Escherichia coli Proteins; D004247:DNA; D001120:Arginine