title: Structural characterization of the H-NS protein from Xylella fastidiosa and its interaction with DNA.
abstract: The nucleoid-associated protein H-NS is a major component of the bacterial nucleoid involved in DNA compaction and transcription regulation. The NMR solution structure of the Xylella fastidiosa H-NS C-terminal domain (residues 56-134) is presented here and consists of two beta-strands and two alpha helices, with one loop connecting the two beta-strands and a second loop connecting the second beta strand and the first helix. The amide (1)H and (15)N chemical shift signals for a sample of XfH-NS(56-134) were monitored in the course of a titration series with a 14-bp DNA duplex. Most of the residues involved in contacts to DNA are located around the first and second loops and in the first helix at a positively charged side of the protein surface. The overall structure of the Xylella H-NS C-terminal domain differ significantly from Escherichia coli and Salmonella enterica H-NS proteins, even though the DNA binding motif in loop 2 adopt similar conformation, as well as β-strand 2 and loop 1. Interestingly, we have also found that the DNA binding site is expanded to include helix 1, which is not seen in the other structures.
authors: Molecular Biology and Genetic Engineering Center, University of Campinas, Campinas, SP, Brazil.
authors: Luciana K
authors: LK
authors: Rosselli-Murai
authors: Maurício L
authors: ML
authors: Sforça
authors: Rogério C
authors: RC
authors: Sassonia
authors: Adriano R
authors: AR
authors: Azzoni
authors: Marcelo J
authors: MJ
authors: Murai
authors: Anete P
authors: AP
authors: de Souza
authors: Ana C
authors: AC
authors: Zeri
mesh_terms: D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000737:chemistry* / Q000378:metabolism*; D004247:DNA / Q000235:genetics / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000737:chemistry* / Q000378:metabolism*; D020862:GC Rich Sequence; D008958:Models, Molecular; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000737:chemistry / Q000378:metabolism; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D016415:Sequence Alignment; D012996:Solutions; D044167:Xylella
chemical_list: D001426:Bacterial Proteins; D004268:DNA-Binding Proteins; C031908:H-NS protein, bacteria; D010446:Peptide Fragments; D012996:Solutions; D004247:DNA