This Article Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Reprints and Permissions Copyright Information Books from ASM Press MicrobeWorld Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Guazzaroni, M.-E. Articles by Ramos, J. L. Search for Related Content PubMed PubMed Citation Articles by Guazzaroni, M.-E. Articles by Ramos, J. L.

 Previous Article  |  Next Article 

Journal of Bacteriology, May 2004, p. 2921-2927, Vol. 186, No. 10
0021-9193/04/$08.00+0     DOI: 10.1128/JB.186.10.2921-2927.2004
Copyright © 2004, American Society for Microbiology. All Rights Reserved.

TtgV Bound to a Complex Operator Site Represses Transcription of the Promoter for the Multidrug and Solvent Extrusion TtgGHI Pump

Department of Biochemistry and Molecular and Cell Biology of Plants, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas, E-18008 Granada, Spain,¹ Center for Structural Biology, Department of Biological Sciences, Imperial College, London, United Kingdom²

Received 29 October 2003/ Accepted 29 January 2004

The TtgGHI efflux pump of Pseudomonas putida extrudes a variety of antibiotics and solvents. We show that the ttgGHI operon is transcribed in vitro and in vivo from a single promoter and not from two overlapping promoters as previously proposed. The expression of this promoter is controlled by the TtgV repressor, whose operator expands through four helical turns that overlap the –10 region of the promoter. We also show that TtgV is released from its operator on binding of effectors such as aliphatic alcohols. Mutational analysis of the ttgGHI promoter revealed that substitutions at –13, –12, and –8 yielded promoters that were unable to drive transcription whereas certain mutations at –9, –11, and –6 to –3 increased expression in vivo. The cause of the increased expression was either a decrease in the affinity of the TtgV protein for its operator or an increase in the affinity of RNA polymerase for the mutant promoters.

This article has been cited by other articles:

• Guazzaroni, M.-E., Gallegos, M.-T., Ramos, J. L., Krell, T. (2007). Different Modes of Binding of Mono- and Biaromatic Effectors to the Transcriptional Regulator TTGV: ROLE IN DIFFERENTIAL DEREPRESSION FROM ITS COGNATE OPERATOR. J. Biol. Chem. 282: 16308-16316 [Abstract] [Full Text]  
• Lacal, J., Busch, A., Guazzaroni, M.-E., Krell, T., Ramos, J. L. (2006). The TodS-TodT two-component regulatory system recognizes a wide range of effectors and works with DNA-bending proteins. Proc. Natl. Acad. Sci. USA 103: 8191-8196 [Abstract] [Full Text]  
• Krell, T., Molina-Henares, A. J., Ramos, J. L. (2006). The IclR family of transcriptional activators and repressors can be defined by a single profile. Protein Sci. 15: 1207-1213 [Abstract] [Full Text]  
• Segura, A., Godoy, P., van Dillewijn, P., Hurtado, A., Arroyo, N., Santacruz, S., Ramos, J.-L. (2005). Proteomic Analysis Reveals the Participation of Energy- and Stress-Related Proteins in the Response of Pseudomonas putida DOT-T1E to Toluene. J. Bacteriol. 187: 5937-5945 [Abstract] [Full Text]  
• Guazzaroni, M.-E., Krell, T., Felipe, A., Ruiz, R., Meng, C., Zhang, X., Gallegos, M.-T., Ramos, J. L. (2005). The Multidrug Efflux Regulator TtgV Recognizes a Wide Range of Structurally Different Effectors in Solution and Complexed with Target DNA: EVIDENCE FROM ISOTHERMAL TITRATION CALORIMETRY. J. Biol. Chem. 280: 20887-20893 [Abstract] [Full Text]