Further studies will probe the resourcefulness of the Escherichia coli genome to evolve pathways for exploiting novel carbon and energy sources and to discover the range of genetic mechanisms available. The fuc regulon, specifying L-fucose utilization, is under positive control by the fucR product. The enzymes encoded by the fuc structural genes have potentials to catalyze the utilization of fucose analogs, such as D-arabinose and L-galactose. Mutations in fucR can alter the inducer specificity of he activator so that these analogs can be metabolized by the fucose system. The nature of numerous fucR mutations that enlarge the metabolic repertoire of the cell will be characterized. The fucO gene encodes and NAD-linked L-1, 2-propanediol oxidoreductase. The normal function of this enzyme is to produce propanediol as an end product of fermentation. Propanediol, however, cannot be salvaged for aerobic growth because it cannot induced fucO expression. Moreover, the enzyme is inactivated during aerobic metabolism. Mutants serially selected for aerobic growth on propanediol synthesize constitutively and oxidoreductase which is resistant to inactivation. Attempts will be made to characterize the structural changes of the oxidoreductase that render the enzyme resistant to aerobic inactivation. Further studies will be undertaken to depict the agents that inactivate the fucO gene product. Ethanol dehydrogenase, encoded by adhE, is another NAD-linked fermentation enzyme. In contrast to fucO, little is known about the transcriptional control of adhE, except that its expression is 10-fold elevated during anaerobic growth. However, like propanediol oxidoreductase, the enzyme is also inactivated by aerobic metabolism. Mutants that utilize ethanol dehydrogenase for growth on ethanol were first isolated by D. Clark and coworkers. Studies will be undertaken to characterize the mechanism of transcriptional control of adhE and to discover the factors that influence the aerobic stability of adhE gene product.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Project (R01)
Project #
2R01GM039693-06
Application #
2179964
Study Section
Special Emphasis Panel (ZRG7-SSS-2 (14))
Project Start
1988-04-01
Project End
1998-03-31
Budget Start
1994-04-01
Budget End
1995-03-31
Support Year
6
Fiscal Year
1994
Total Cost
Indirect Cost
Name
Harvard University
Department
Microbiology/Immun/Virology
Type
Schools of Medicine
DUNS #
082359691
City
Boston
State
MA
Country
United States
Zip Code
02115
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Membrillo-Hernandez, J; Lin, E C (1999) Regulation of expression of the adhE gene, encoding ethanol oxidoreductase in Escherichia coli: transcription from a downstream promoter and regulation by fnr and RpoS. J Bacteriol 181:7571-9
De Wulf, P; Kwon, O; Lin, E C (1999) The CpxRA signal transduction system of Escherichia coli: growth-related autoactivation and control of unanticipated target operons. J Bacteriol 181:6772-8
McGuire, A M; De Wulf, P; Church, G M et al. (1999) A weight matrix for binding recognition by the redox-response regulator ArcA-P of Escherichia coli. Mol Microbiol 32:219-21
Pogliano, J; Lynch, A S; Belin, D et al. (1997) Regulation of Escherichia coli cell envelope proteins involved in protein folding and degradation by the Cpx two-component system. Genes Dev 11:1169-82
Aristarkhov, A; Mikulskis, A; Belasco, J G et al. (1996) Translation of the adhE transcript to produce ethanol dehydrogenase requires RNase III cleavage in Escherichia coli. J Bacteriol 178:4327-32
Lynch, A S; Lin, E C (1996) Transcriptional control mediated by the ArcA two-component response regulator protein of Escherichia coli: characterization of DNA binding at target promoters. J Bacteriol 178:6238-49
Chen, Y M; Lin, E C (1991) Regulation of the adhE gene, which encodes ethanol dehydrogenase in Escherichia coli. J Bacteriol 173:8009-13
Hidalgo, E; Chen, Y M; Lin, E C et al. (1991) Molecular cloning and DNA sequencing of the Escherichia coli K-12 ald gene encoding aldehyde dehydrogenase. J Bacteriol 173:6118-23

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