This Article Full Text Full Text (PDF) Other Versions of this Article: JB.00229-07v1 189/15/5534    most recent 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 Ogasawara, H. Articles by Ishihama, A. Search for Related Content PubMed PubMed Citation Articles by Ogasawara, H. Articles by Ishihama, A.

PdhR (Pyruvate Dehydrogenase Complex Regulator) Controls the Respiratory Electron Transport System in Escherichia coli

Department of Frontier Bioscience,¹ Research Center for Micro-Nano Technology, Hosei University, Koganei, Tokyo 184-8584,² Nippon Institute for Biological Science, Ome, Tokyo 198-0024,³ Department of Advanced Bioscience, Kinki University, Nara 631-8505, Japan⁴

Received 11 February 2007/ Accepted 10 May 2007

The pyruvate dehydrogenase (PDH) multienzyme complex plays a key role in the metabolic interconnection between glycolysis and the citric acid cycle. Transcription of the Escherichia coli genes for all three components of the PDH complex in the pdhR-aceEF-lpdA operon is repressed by the pyruvate-sensing PdhR, a GntR family transcription regulator, and derepressed by pyruvate. After a systematic search for the regulation targets of PdhR using genomic systematic evolution of ligands by exponential enrichment (SELEX), we have identified two novel targets, ndh, encoding NADH dehydrogenase II, and cyoABCDE, encoding the cytochrome bo-type oxidase, both together forming the pathway of respiratory electron transport downstream from the PDH cycle. PDH generates NADH, while Ndh and CyoABCDE together transport electrons from NADH to oxygen. Using gel shift and DNase I footprinting assays, the PdhR-binding site (PdhR box) was defined, which includes a palindromic consensus sequence, ATTGGTNNNACCAAT. The binding in vitro of PdhR to the PdhR box decreased in the presence of pyruvate. Promoter assays in vivo using a two-fluorescent-protein vector also indicated that the newly identified operons are repressed by PdhR and derepressed by the addition of pyruvate. Taken together, we propose that PdhR is a master regulator for controlling the formation of not only the PDH complex but also the respiratory electron transport system.

Published ahead of print on 18 May 2007.

This article has been cited by other articles:

• Aguilera, L., Campos, E., Gimenez, R., Badia, J., Aguilar, J., Baldoma, L. (2008). Dual Role of LldR in Regulation of the lldPRD Operon, Involved in L-Lactate Metabolism in Escherichia coli. J. Bacteriol. 190: 2997-3005 [Abstract] [Full Text]