title: Target genes, consensus binding site, and role of phosphorylation for the response regulator MtrA of Corynebacterium glutamicum.
abstract: The two-component signal transduction system consisting of the sensor kinase MtrB and the response regulator MtrA is highly conserved in corynebacteria and mycobacteria. Whereas mtrA of Mycobacterium tuberculosis was reported to be essential, we recently succeeded in creating ΔmtrAB and ΔmtrA deletion mutants of Corynebacterium glutamicum and provided evidence that mepA and nlpC, both encoding putative cell wall peptidases, are directly repressed by MtrA, whereas proP and betP, both encoding carriers for compatible solutes, are directly activated by MtrA. In the present study, novel MtrA target genes were identified, including mepB, encoding another putative cell wall peptidase. The repressor or activator functions of MtrA correlate with the distance between the MtrA binding site and the transcriptional start site. From the identified binding sites within 20 target promoters, a 19-bp MtrA consensus motif was derived which represents a direct repeat of 8 base pairs separated by 3 base pairs. Gene expression of a strain containing MtrA with a D53N mutation instead of wild-type MtrA resembled that of a ΔmtrA mutant, indicating that MtrA is active in its phosphorylated form. This result was confirmed by electrophoretic mobility shift assays with phosphorylated MtrA which showed an increased binding affinity.
authors.affiliation: Institut für Bio- und Geowissenschaften, IBG-1: Biotechnologie, Forschungszentrum Jülich, D-52425 Jülich, Germany. m.bott@fz-juelich.de
authors.forename: Melanie
authors.initials: M
authors.lastname: Brocker
authors.forename: Christina
authors.initials: C
authors.lastname: Mack
authors.forename: Michael
authors.initials: M
authors.lastname: Bott
mesh_terms: D018528:ATP-Binding Cassette Transporters / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D001483:Base Sequence; D001665:Binding Sites; D048230:Corynebacterium glutamicum / Q000235:genetics / Q000378:metabolism*; D004252:DNA Mutational Analysis; D004269:DNA, Bacterial / Q000378:metabolism; D011485:Protein Binding; D011487:Protein Conformation; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction / Q000502:physiology
chemical_list: D018528:ATP-Binding Cassette Transporters; D001426:Bacterial Proteins; D004269:DNA, Bacterial; C100938:MtrA protein, Bacteria; D012333:RNA, Messenger