Characterization of the LacI-type transcriptional repressor RbsR controlling ribose transport in Corynebacterium glutamicum ATCC 13032.
The gene products of the rbsRACBD (rbs) operon of C. glutamicum (cg1410-cg1414) encode a ribose-specific ATP-binding cassette (ABC) transport system and its corresponding regulatory protein (RbsR). Deletion of the structural genes rbsACBD prohibited ribose uptake. Deletion of the regulatory gene rbsR resulted in an increased mRNA level of the whole operon. Analysis of the promoter region of the rbs operon by electrophoretic mobility shift assays identified a catabolite-responsive element (cre)-like sequence as the RbsR-binding site. Additional RbsR-binding sites were identified in front of the recently characterized uriR operon (uriR-rbsK1-uriT-uriH) and the ribokinase gene rbsK2. In vitro, the repressor RbsR bound to its targets in the absence of an effector. A probable negative effector of RbsR in vivo is ribose 5-phosphate or a derivative thereof, since in a ribokinase (rbsK1 rbsK2) double mutant, no derepression of the rbs operon in the presence of ribose was observed. Analysis of the ribose stimulon in the C. glutamicum wild-type revealed transcriptional induction of the uriR and rbs operons as well as of the rbsK2 gene. The inconsistency between the existence of functional RbsR-binding sites upstream of the ribokinase genes, their transcriptional induction during growth on ribose, and the missing induction in the rbsR mutant suggested the involvement of a second transcriptional regulator. Simultaneous deletion of the regulatory genes rbsR and uriR finally demonstrated a transcriptional co-control of the rbs and uriR operons and the rbsK2 gene by both regulators, RbsR and UriR, which were furthermore shown to recognize the same cognate DNA sequences in the operators of their target genes.
Nentwich
Svenja S
SS
Institut für Genomforschung und Systembiologie, Centrum für Biotechnologie, Universität Bielefeld, Universitätsstrasse 27, 33615 Bielefeld, Germany.
Brinkrolf
Karina
K
Institut für Genomforschung und Systembiologie, Centrum für Biotechnologie, Universität Bielefeld, Universitätsstrasse 27, 33615 Bielefeld, Germany.
Gaigalat
Lars
L
Institut für Genomforschung und Systembiologie, Centrum für Biotechnologie, Universität Bielefeld, Universitätsstrasse 27, 33615 Bielefeld, Germany.
Hüser
Andrea T
AT
Institut für Genomforschung und Systembiologie, Centrum für Biotechnologie, Universität Bielefeld, Universitätsstrasse 27, 33615 Bielefeld, Germany.
Rey
Daniel A
DA
Institut für Genomforschung und Systembiologie, Centrum für Biotechnologie, Universität Bielefeld, Universitätsstrasse 27, 33615 Bielefeld, Germany.
Mohrbach
Tobias
T
Institut für Biochemie, Universität zu Köln, Zülpicher Strasse 47, 50674 Köln, Germany.
Marin
Kay
K
Institut für Biochemie, Universität zu Köln, Zülpicher Strasse 47, 50674 Köln, Germany.
Pühler
Alfred
A
Institut für Genomforschung und Systembiologie, Centrum für Biotechnologie, Universität Bielefeld, Universitätsstrasse 27, 33615 Bielefeld, Germany.
Tauch
Andreas
A
Institut für Genomforschung und Systembiologie, Centrum für Biotechnologie, Universität Bielefeld, Universitätsstrasse 27, 33615 Bielefeld, Germany.
Kalinowski
Jörn
J
Institut für Genomforschung und Systembiologie, Centrum für Biotechnologie, Universität Bielefeld, Universitätsstrasse 27, 33615 Bielefeld, Germany.
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; D001692:Biological Transport; D048230:Corynebacterium glutamicum / Q000235:genetics / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D017353:Gene Deletion; D015964:Gene Expression Regulation, Bacterial; D008969:Molecular Sequence Data; D009876:Operon; D012097:Repressor Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D012266:Ribose / Q000378:metabolism*
D018528:ATP-Binding Cassette Transporters; D001426:Bacterial Proteins; D004268:DNA-Binding Proteins; D012097:Repressor Proteins; D012266:Ribose