title: Similarity and divergence between the RNA polymerase alpha subunits from hyperthermophilic Thermotoga maritima and mesophilic Escherichia coli bacteria.
abstract: The alpha subunit (alphaTm) of Thermotoga maritima RNA polymerase has been characterized to investigate its role in transcriptional regulation in one of the few known anaerobic hyperthermophilic bacteria. The highly thermostable alphaTm shares 54% similarity with its Escherichia coli analogue (alphaEc). The T. maritima rpoA gene coding the alpha subunit does not complement the thermosensitive rpoA112 mutation of E. coli. However, alphaTm and alphaEc show similar folding patterns as determined by circular dichroism. Purified alphaTm binds to the T. maritima PargGo promoter region (probably to a UP-element) and Arg282 appears to be crucial for DNA binding. The thermostable protein is also able to interact with transcription regulatory proteins, like ArgR from T. neapolitana or CRP from E. coli. These data indicate that the RNA polymerase alpha subunit might play a crucial role in the modulation of gene expression in hyperthermophiles.
authors.affiliation: Unité Biotechnologie, Biocatalyse et Biorégulation, CNRS UMR 6204, Faculté des Sciences et des Techniques, Université de Nantes, 2 rue de la Houssinière, 44322 Nantes cedex 03, France. frederique.braun@univ-nantes.fr
authors.forename: Frederique
authors.initials: F
authors.lastname: Braun
authors.forename: Fanny B
authors.initials: FB
authors.lastname: Marhuenda
authors.forename: Amelie
authors.initials: A
authors.lastname: Morin
authors.forename: Laetitia
authors.initials: L
authors.lastname: Guevel
authors.forename: Fabrice
authors.initials: F
authors.lastname: Fleury
authors.forename: Masayuki
authors.initials: M
authors.lastname: Takahashi
authors.forename: Vehary
authors.initials: V
authors.lastname: Sakanyan
mesh_terms: D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000235:genetics; D001483:Base Sequence; D004268:DNA-Binding Proteins / Q000235:genetics; D012321:DNA-Directed RNA Polymerases / Q000235:genetics* / Q000502:physiology; D004926:Escherichia coli / Q000235:genetics*; D015964:Gene Expression Regulation, Bacterial; D005798:Genes, Bacterial; D005816:Genetic Complementation Test / Q000379:methods; D008969:Molecular Sequence Data; D011401:Promoter Regions, Genetic; D011485:Protein Binding; D017386:Sequence Homology, Amino Acid; D020124:Thermotoga maritima / Q000235:genetics*; D014157:Transcription Factors / Q000235:genetics
chemical_list: D001426:Bacterial Proteins; D004268:DNA-Binding Proteins; D014157:Transcription Factors; D012321:DNA-Directed RNA Polymerases; C113275:RNA polymerase alpha subunit