title: The DNA static curvature has a role in the regulation of the ompS1 porin gene in Salmonella enterica serovar Typhi.
abstract: The DNA static curvature has been described to play a key role as a regulatory element in the transcription process of several bacterial genes. Here, the role of DNA curvature in the expression of the ompS1 porin gene in Salmonella enterica serovar Typhi is described. The web server mutacurve was used to predict mutations that diminished or restored the extent of DNA curvature in the 5' regulatory region of ompS1. Using these predictions, curvature was diminished by site-directed mutagenesis of only two residues, and curvature was restored by further mutagenesis of the same two residues. Lowering the extent of DNA curvature resulted in an increase in ompS1 expression and in the diminution of the affinity of the silencer proteins H-NS and StpA for the ompS1 5' regulatory region. These mutations were in a region shown not to contain the H-NS nucleation site, consistent with the notion that the effect on expression was due to changes in DNA structural topology.
authors.affiliation: Departamento de Microbiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Morelos 62260, Mexico.
authors.forename: Miguel Ángel
authors.initials: MÁ
authors.lastname: De la Cruz
authors.affiliation: Departamento de Microbiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Morelos 62260, Mexico.
authors.forename: Enrique
authors.initials: E
authors.lastname: Merino
authors.affiliation: Departamento de Microbiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Morelos 62260, Mexico.
authors.forename: Ricardo
authors.initials: R
authors.lastname: Oropeza
authors.affiliation: Departamento de Microbiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Morelos 62260, Mexico.
authors.forename: Juan
authors.initials: J
authors.lastname: Téllez
authors.affiliation: Departamento de Microbiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Morelos 62260, Mexico.
authors.forename: Edmundo
authors.initials: E
authors.lastname: Calva
mesh_terms: D001425:Bacterial Outer Membrane Proteins / Q000096:biosynthesis / Q000235:genetics; D001426:Bacterial Proteins / Q000378:metabolism; D001483:Base Sequence; D001833:Body Temperature Regulation; D004269:DNA, Bacterial / Q000502:physiology*; D004268:DNA-Binding Proteins / Q000378:metabolism; D015964:Gene Expression Regulation, Bacterial; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D018272:Porins / Q000096:biosynthesis* / Q000235:genetics; D012045:Regulatory Sequences, Nucleic Acid; D012485:Salmonella typhi / Q000235:genetics / Q000378:metabolism; D012984:Software; D014158:Transcription, Genetic; D014882:Water-Electrolyte Balance
chemical_list: D001425:Bacterial Outer Membrane Proteins; D001426:Bacterial Proteins; D004269:DNA, Bacterial; D004268:DNA-Binding Proteins; C031908:H-NS protein, bacteria; D018272:Porins