The formate-nitrate reductase pathway in Escherichia coli is being employed as an experimental system for studying the biogenesis of an organized, membrane-bound multienzyme complex. The formate-nitrate reductase pathway in E. coli is an electron transport system which is organized in the cell membrane so that energy, in the form of a protein gradient, is generated during transfer of electrons from formate to nitrate. Our long range goal is to define the molecular mechanisms in the biosynthesis of the component proteins, their insertion into the membrane, their assembly into multisubunit complexes and the incorporation of non-protein cofactor components into the functional enzyme complexes. Our immediate specific aims are focused on one of the enzyme complexes of this pathway, nitrate reductase; We propose to utilize biochemical, genetic and recombinant DNA techniques to determine (1) the structure of the nar operon and the specific component involved in its regulation, (2) the products of the nar operon, including the enzyme subunits and other possible regulatory components, (3) the role of specific subunits in the interaction of the enzyme with the membrane both in vitro and in vivo. Longer range studies will initiate studies on the role of specific protein domains on subunit interactions and insertion into the membrane.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Project (R01)
Project #
5R01GM019511-16
Application #
3269668
Study Section
Microbial Physiology and Genetics Subcommittee 2 (MBC)
Project Start
1976-06-01
Project End
1989-07-31
Budget Start
1987-08-01
Budget End
1988-07-31
Support Year
16
Fiscal Year
1987
Total Cost
Indirect Cost
Name
University of Texas Health Science Center Houston
Department
Type
Schools of Medicine
DUNS #
City
Houston
State
TX
Country
United States
Zip Code
77225
Walker, M S; DeMoss, J A (1994) NarL-phosphate must bind to multiple upstream sites to activate transcription from the narG promoter of Escherichia coli. Mol Microbiol 14:633-41
Walker, M S; DeMoss, J A (1993) Phosphorylation and dephosphorylation catalyzed in vitro by purified components of the nitrate sensing system, NarX and NarL. J Biol Chem 268:8391-3
Walker, M S; DeMoss, J A (1992) Role of alternative promoter elements in transcription from the nar promoter of Escherichia coli. J Bacteriol 174:1119-23
Bonnefoy, V; DeMoss, J A (1992) Identification of functional cis-acting sequences involved in regulation of narK gene expression in Escherichia coli. Mol Microbiol 6:3595-602
Dubourdieu, M; DeMoss, J A (1992) The narJ gene product is required for biogenesis of respiratory nitrate reductase in Escherichia coli. J Bacteriol 174:867-72
Dong, X R; Li, S F; DeMoss, J A (1992) Upstream sequence elements required for NarL-mediated activation of transcription from the narGHJI promoter of Escherichia coli. J Biol Chem 267:14122-8
Walker, M S; DeMoss, J A (1991) Promoter sequence requirements for Fnr-dependent activation of transcription of the narGHJI operon. Mol Microbiol 5:353-60
DeMoss, J A; Hsu, P Y (1991) NarK enhances nitrate uptake and nitrite excretion in Escherichia coli. J Bacteriol 173:3303-10
Sodergren, E J; DeMoss, J A (1988) narI region of the Escherichia coli nitrate reductase (nar) operon contains two genes. J Bacteriol 170:1721-9
Sodergren, E J; Hsu, P Y; DeMoss, J A (1988) Roles of the narJ and narI gene products in the expression of nitrate reductase in Escherichia coli. J Biol Chem 263:16156-62

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