title: Comparative genomics of pyridoxal 5'-phosphate-dependent transcription factor regulons inBacteria.
abstract: The MocR-subfamily transcription factors (MocR-TFs) characterized by the GntR-family DNA-binding domain and aminotransferase-like sensory domain are broadly distributed among certain lineages ofBacteria. Characterized MocR-TFs bind pyridoxal 5'-phosphate (PLP) and control transcription of genes involved in PLP, gamma aminobutyric acid (GABA) and taurine metabolism via binding specific DNA operator sites. To identify putative target genes and DNA binding motifs of MocR-TFs, we performed comparative genomics analysis of over 250 bacterial genomes. The reconstructed regulons for 825 MocR-TFs comprise structural genes from over 200 protein families involved in diverse biological processes. Using the genome context and metabolic subsystem analysis we tentatively assigned functional roles for 38 out of 86 orthologous groups of studied regulators. Most of these MocR-TF regulons are involved in PLP metabolism, as well as utilization of GABA, taurine and ectoine. The remaining studied MocR-TF regulators presumably control genes encoding enzymes involved in reduction/oxidation processes, various transporters and PLP-dependent enzymes, for example aminotransferases. Predicted DNA binding motifs of MocR-TFs are generally similar in each orthologous group and are characterized by two to four repeated sequences. Identified motifs were classified according to their structures. Motifs with direct and/or inverted repeat symmetry constitute the majority of inferred DNA motifs, suggesting preferable TF dimerization in head-to-tail or head-to-head configuration. The obtained genomic collection ofin silicoreconstructed MocR-TF motifs and regulons inBacteriaprovides a basis for future experimental characterization of molecular mechanisms for various regulators in this family.
authors.affiliation: 1​A. A. Kharkevich Institute for Information Transmission Problems, Russian Academy of Science, Moscow, Russia.
authors.forename: Inna A
authors.initials: IA
authors.lastname: Suvorova
authors.affiliation: 1​A. A. Kharkevich Institute for Information Transmission Problems, Russian Academy of Science, Moscow, Russia.|2​Sanford-Burnham-Prebys Medical Discovery Institute, La Jolla, CA 92037, USA.
authors.forename: Dmitry A
authors.initials: DA
authors.lastname: Rodionov
mesh_terms: D001419:Bacteria / Q000235:genetics*; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D001665:Binding Sites; D016680:Genome, Bacterial; D023281:Genomics; D059372:Nucleotide Motifs; D010710:Phosphates / Q000378:metabolism; D018085:Regulon / Q000235:genetics*; D014157:Transcription Factors / Q000235:genetics*
chemical_list: D001426:Bacterial Proteins; D010710:Phosphates; D014157:Transcription Factors
keywords: DNA motif; bacteria; comparative genomics; regulon reconstruction; transcription factor