Glutamine amidotransferases are a family of enzymes that utilize the amide of glutamine in biosynthesis. they provide the main route for incorporation of nitrogen into amino acids, purine and pyrimidine nucleotides, amino sugars and coenzymes. There are 3 glutamine amidotransferases in the pathway for purine nucleotide synthesis. Glutamine PRPP amidotransferase catalyzes step 1 and is the key regulatory enzyme in the de novo pathway. The long term objective of this research is to determine basic mechanisms for glutamine amidotransferase catalysis and regulation as well as gene regulation in microorganisms. There are 4 specific aims. (1) Determine mechanisms for regulation of glutamine PRPP amidotransferase. The experiments focus on two regulatory events: nucleotide endproduct inhibition and processing of an NH2-terminal pro-peptide in the Bacillus subtilis enzyme. (2) Determine mechanisms for genetic regulation of Escherichia coli genes involved in the IMP to AMP and GMP branches of the pathway. (3) Determine how purine bases bind to E. coli pur regulon aporepressor and how this binding promotes the specific holorepressor-DNA interactions. (4) Determine mechanisms for transcriptional regulation of the B. subtilis pur operon which encodes the 10 step pathway to IMP and regulation of genes purA, guaA and guaB for the IMP to AMP and GMP branches. Finally, experiments are planned to determine the importance of B. subtilis pur operon gene overlaps in establishing the translational stoichiometry for enzyme synthesis. Purine metabolism has been a fertile area for development of drugs against a variety of diseases. Two inhibitors of glutamine amidotransferases in the purine pathway, acivicin and triciribine have antineoplastic activity.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Method to Extend Research in Time (MERIT) Award (R37)
Project #
5R37GM024658-25
Application #
2174296
Study Section
Microbial Physiology and Genetics Subcommittee 2 (MBC)
Project Start
1977-07-01
Project End
1997-06-30
Budget Start
1995-07-01
Budget End
1996-06-30
Support Year
25
Fiscal Year
1995
Total Cost
Indirect Cost
Name
Purdue University
Department
Biochemistry
Type
Schools of Earth Sciences/Natur
DUNS #
072051394
City
West Lafayette
State
IN
Country
United States
Zip Code
47907
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Bera, Aloke Kumar; Zhu, Jianghai; Zalkin, Howard et al. (2003) Functional dissection of the Bacillus subtilis pur operator site. J Bacteriol 185:4099-109
Bera, A K; Smith, J L; Zalkin, H (2000) Dual role for the glutamine phosphoribosylpyrophosphate amidotransferase ammonia channel. Interdomain signaling and intermediate channeling. J Biol Chem 275:7975-9
Bera, A K; Chen, S; Smith, J L et al. (2000) Temperature-dependent function of the glutamine phosphoribosylpyrophosphate amidotransferase ammonia channel and coupling with glycinamide ribonucleotide synthetase in a hyperthermophile. J Bacteriol 182:3734-9
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Bera, A K; Chen, S; Smith, J L et al. (1999) Interdomain signaling in glutamine phosphoribosylpyrophosphate amidotransferase. J Biol Chem 274:36498-504
Li, S; Smith, J L; Zalkin, H (1999) Mutational analysis of Bacillus subtilis glutamine phosphoribosylpyrophosphate amidotransferase propeptide processing. J Bacteriol 181:1403-8
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Sinha, S; Rappu, P; Lange, S C et al. (1999) Crystal structure of Bacillus subtilis YabJ, a purine regulatory protein and member of the highly conserved YjgF family. Proc Natl Acad Sci U S A 96:13074-9
Lu, F; Brennan, R G; Zalkin, H (1998) Escherichia coli purine repressor: key residues for the allosteric transition between active and inactive conformations and for interdomain signaling. Biochemistry 37:15680-90

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