It is proposed to study the metabolic regulation and mechanism of catalysis of the essential biosynthetic enzyme phosphoribosylpyrophosphate (PRPP) synthetase from the enteric bacterium Salmonella typhimurium. This enzyme is of particular interest because (a) PRPP is the first step in a universal, highly branched pathway leading to all nucleotides, two amino acids, and two coenzymes; (b) the enzyme catalyzes an unusual pyrophosphoryl group transfer reaction, and (c) PRPP metabolism is known to play an important role in a number of inherited metabolic diseases leading to anemia or hyperuricemia and gout. It is proposed to clone the structural gene for PRPP synthetase from S. typhimurium and to determine its nucleotide sequence. This will provide the primary structure of the enzyme; active site amino acid residues will be located in the sequence by chemical modification with active site-directed reagents and peptide mapping. These results, combined with previous and proposed mechanistic studies, should provide a much refined picture of enzymic catalysis by PRPP synthetase. The regulation of transcription from the PRPP synthetase gene will be studied by sequencing adjacent control regions and by studying transcription in vitro using DNA isolated on recombinant plasmids. The function of a second gene affecting PRPP synthetase activity will be probed by similar techniques.

National Institute of Health (NIH)
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
Research Project (R01)
Project #
Application #
Study Section
Physiological Chemistry Study Section (PC)
Project Start
Project End
Budget Start
Budget End
Support Year
Fiscal Year
Total Cost
Indirect Cost
University of Illinois Urbana-Champaign
Schools of Arts and Sciences
United States
Zip Code
Becker, M A; Smith, P R; Taylor, W et al. (1995) The genetic and functional basis of purine nucleotide feedback-resistant phosphoribosylpyrophosphate synthetase superactivity. J Clin Invest 96:2133-41
Becker, M A; Nosal, J M; Switzer, R L et al. (1994) Point mutations in PRPS1, the gene encoding the PRPP synthetase (PRS) 1 isoform, underlie X-linked PRS superactivity associated with purine nucleotide inhibitor-resistance. Adv Exp Med Biol 370:707-10
Post, D A; Hove-Jensen, B; Switzer, R L (1993) Characterization of the hemA-prs region of the Escherichia coli and Salmonella typhimurium chromosomes: identification of two open reading frames and implications for prs expression. J Gen Microbiol 139:259-66
Roessler, B J; Nosal, J M; Smith, P R et al. (1993) Human X-linked phosphoribosylpyrophosphate synthetase superactivity is associated with distinct point mutations in the PRPS1 gene. J Biol Chem 268:26476-81
Nosal, J M; Switzer, R L; Becker, M A (1993) Overexpression, purification, and characterization of recombinant human 5-phosphoribosyl-1-pyrophosphate synthetase isozymes I and II. J Biol Chem 268:10168-75
Post, D A; Switzer, R L (1991) prsB is an allele of the Salmonella typhimurium prsA gene: characterization of a mutant phosphoribosylpyrophosphate synthetase. J Bacteriol 173:1978-86
Harlow, K W; Switzer, R L (1990) Sulfhydryl chemistry of Salmonella typhimurium phosphoribosylpyrophosphate synthetase: identification of two classes of cysteinyl residues. Arch Biochem Biophys 276:466-72
Arnvig, K; Hove-Jensen, B; Switzer, R L (1990) Purification and properties of phosphoribosyl-diphosphate synthetase from Bacillus subtilis. Eur J Biochem 192:195-200
Harlow, K W; Switzer, R L (1990) Chemical modification of Salmonella typhimurium phosphoribosylpyrophosphate synthetase with 5'-(p-fluorosulfonylbenzoyl)adenosine. Identification of an active site histidine. J Biol Chem 265:5487-93
Bower, S G; Harlow, K W; Switzer, R L et al. (1989) Characterization of the Escherichia coli prsA1-encoded mutant phosphoribosylpyrophosphate synthetase identifies a divalent cation-nucleotide binding site. J Biol Chem 264:10287-91

Showing the most recent 10 out of 11 publications