title: Chemical modification of Salmonella typhimurium phosphoribosylpyrophosphate synthetase with 5'-(p-fluorosulfonylbenzoyl)adenosine. Identification of an active site histidine.
abstract: Liquid chromatographic procedures have been developed for rapidly locating the site of reaction of chemical modification reagents with Salmonella typhimurium 5-phosphoribosyl-alpha-1-pyrophosphate (PRPP) synthetase. The enzyme was reacted with the active site-directed reagent 5'-(p-fluorosulfonylbenzoyl)adenosine (FSBA). FSBA bound to the enzyme with an apparent KD of 1.7 +/- 0.4 mM. The enzyme was inactivated during the reaction, and a limiting stoichiometry of 1.2 mol of FSBA/mol of enzyme subunit corresponded to complete inactivation. Inclusion of ATP in the reaction protected the enzyme from inactivation and incorporation of the reagent. Inclusion of ribose 5-phosphate increased the rate of reaction of PRPP synthetase with FSBA. Amino acid analyses of acid hydrolysates of modified enzyme failed to detect any known FSBA-amino acid adducts. Tryptic digestion of 5'-(p-fluorosulfonylbenzoyl)-[3H]adenosine-modified enzyme at pH 7.0 yielded a single radioactive peptide. The peptide, TR-1, was subjected to combined V8 and Asp-N protease digestion, and a single radioactive peptide was isolated. This radioactive peptide yielded the sequence Asp-Leu-His-Ala-Glu, which corresponded to amino acid residues 128-132 in S. typhimurium PRPP synthetase. No radioactivity was associated with any of the phenylthiohydantoin-amino acid fractions, all of which were recovered in good yield. A majority of the radioactivity was found in the waste effluent (64%) and on the glass fiber filter loaded into the sequenator (23%). The lability of the modification and the sequence of this peptide indicate His130 as the site of reaction with FSBA.
authors.affiliation: Department of Biochemistry, University of Illinois, Urbana 61801.
authors.forename: K W
authors.initials: KW
authors.lastname: Harlow
authors.forename: R L
authors.initials: RL
authors.lastname: Switzer
mesh_terms: D000241:Adenosine / Q000031:analogs & derivatives* / Q000378:metabolism / Q000494:pharmacology; D000255:Adenosine Triphosphate / Q000494:pharmacology; D000595:Amino Acid Sequence; D000596:Amino Acids / Q000032:analysis; D016282:Aspartic Acid Endopeptidases; D001665:Binding Sites; D055598:Chemical Phenomena; D002621:Chemistry; D010450:Endopeptidases / Q000378:metabolism; D006639:Histidine; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000302:isolation & purification / Q000378:metabolism; D010770:Phosphotransferases / Q000037:antagonists & inhibitors*; D012268:Ribose-Phosphate Pyrophosphokinase / Q000032:analysis / Q000037:antagonists & inhibitors* / Q000378:metabolism; D012267:Ribosemonophosphates / Q000494:pharmacology; D012486:Salmonella typhimurium / Q000201:enzymology*; D012697:Serine Endopeptidases / Q000378:metabolism; D014357:Trypsin / Q000378:metabolism
chemical_list: D000596:Amino Acids; D010446:Peptide Fragments; D012267:Ribosemonophosphates; C031626:ribose-5-phosphate; D006639:Histidine; C010959:5'-(4-fluorosulfonylbenzoyl)adenosine; D000255:Adenosine Triphosphate; D010770:Phosphotransferases; D012268:Ribose-Phosphate Pyrophosphokinase; D010450:Endopeptidases; D012697:Serine Endopeptidases; C028344:glutamyl endopeptidase; D014357:Trypsin; D016282:Aspartic Acid Endopeptidases; D000241:Adenosine