Abstract

In biological systems, most processes are under the control of a variety of regulatory mechanisms. For example, the glyoxylate bypass of Escherichia coli is controlled by the phosphorylation of isocitrate dehydrogenase (IDH) and by the regulation of the expression of the glyoxylate bypass operon. Our long-term goal is to characterize these regulatory mechanisms and to determine how they are coordinated. The IDH phosphorylation cycle is catalyzed by a single, bifunctional protein: IDH kinase/phosphatase. Under this proposal, we will study the structure of this bifunctional protein and determine how it specifically recognizes and phosphorylates IDH. In pursuit of these goals, we will characterize the effects of mutations in the genes which encode IDH kinase/phosphatase and IDH. We will also pursue X-ray crystallographic analyses of these proteins and of the complexes which they form. The glyoxylate bypass operon encodes the regulatory and metabolic enzymes of the glyoxylate bypass. Expression of this operon responds to a wide variety of carbon sources and to the availability of molecular oxygen. A goal of this project is to identify the mechanisms by which the expression of this operon is controlled. Under this proposal, we will focus on the repressor protein encoded by iclR. We will also evaluate the possible roles of a variety of other trans-acting factors.

  Funding Agency

Agency
National Institute of Health (NIH)
Institute
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
Type
Research Project (R01)
Project #
5R01DK040486-05
Application #
3240794
Study Section
Physiological Chemistry Study Section (PC)
Project Start
1988-09-01
Project End
1996-08-31
Budget Start
1992-09-01
Budget End
1993-08-31
Support Year
5
Fiscal Year
1992
Total Cost
Indirect Cost

  Institution

Name
University of Minnesota Twin Cities
Department
Type
Schools of Medicine
DUNS #
168559177
City
Minneapolis
State
MN
Country
United States
Zip Code
55455

  Publications

Miller, S P; Chen, R; Karschnia, E J et al. (2000) Locations of the regulatory sites for isocitrate dehydrogenase kinase/phosphatase. J Biol Chem 275:833-9
Finer-Moore, J; Tsutakawa, S E; Cherbavaz, D R et al. (1997) Access to phosphorylation in isocitrate dehydrogenase may occur by domain shifting. Biochemistry 36:13890-6
Pan, B; Unnikrishnan, I; LaPorte, D C (1996) The binding site of the IclR repressor protein overlaps the promoter of aceBAK. J Bacteriol 178:3982-4
Resnik, E; Pan, B; Ramani, N et al. (1996) Integration host factor amplifies the induction of the aceBAK operon of Escherichia coli by relieving IclR repression. J Bacteriol 178:2715-7
Gui, L; Sunnarborg, A; LaPorte, D C (1996) Regulated expression of a repressor protein: FadR activates iclR. J Bacteriol 178:4704-9
Gui, L; Sunnarborg, A; Pan, B et al. (1996) Autoregulation of iclR, the gene encoding the repressor of the glyoxylate bypass operon. J Bacteriol 178:321-4
Miller, S P; Karschnia, E J; Ikeda, T P et al. (1996) Isocitrate dehydrogenase kinase/phosphatase. Kinetic characteristics of the wild-type and two mutant proteins. J Biol Chem 271:19124-8
LaPorte, D C (1993) The isocitrate dehydrogenase phosphorylation cycle: regulation and enzymology. J Cell Biochem 51:14-8
Chung, T; Resnik, E; Stueland, C et al. (1993) Relative expression of the products of glyoxylate bypass operon: contributions of transcription and translation. J Bacteriol 175:4572-5
Firestone, J A; Browning, M D (1992) Synapsin II phosphorylation and catecholamine release in bovine adrenal chromaffin cells: additive effects of histamine and nicotine. J Neurochem 58:441-7

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