title: The thiJ locus and its relation to phosphorylation of hydroxymethylpyrimidine in Escherichia coli.
abstract: Extracts from Escherichia coli K-12 contained two distinct enzymes capable of catalysing the phosphorylation of hydroxymethylpyrimidine (HMP) to HMP monophosphate: pyridoxine kinase (EC 2.7.1.35) and an enzyme that has not previously been genetically analysed, HMP kinase (EC 2.7.1.49). Two distinct genes, pdxL and thiJ, specify the activities of the former and latter enzymes, respectively. The inactivation of both genes by independent mutations in the same cell resulted in the complete loss of HMP kinase activity. Experiments with a series of strains that carry mutations in thiC, thiC pdxB, thiC pdxB pdxL and thiC pdxB pdxL thiJ revealed that the ability of the double mutant (pdxL thiJ) to utilize HMP in thiamin pyrophosphate biosynthesis was restored by introducing the wild-type allele corresponding to the thiJ mutation. The thiJ locus was mapped on the chromosome near the thiD and thiM loci, which govern the activities of phosphomethylpyrimidine kinase (EC 2.7.4.7) and hydroxyethylthiazole kinase (EC 2.7.1.50), respectively.
authors.affiliation: Department of Food and Nutrition, Yamaguchi Prefectural University, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Mizote
authors.forename: M
authors.initials: M
authors.lastname: Tsuda
authors.forename: T
authors.initials: T
authors.lastname: Nakazawa
authors.forename: H
authors.initials: H
authors.lastname: Nakayama
mesh_terms: D002874:Chromosome Mapping; D004352:Drug Resistance, Microbial; D004926:Escherichia coli / Q000187:drug effects / Q000201:enzymology* / Q000235:genetics / Q000378:metabolism; D005798:Genes, Bacterial / Q000235:genetics*; D016296:Mutagenesis; D010766:Phosphorylation; D017853:Phosphotransferases (Alcohol Group Acceptor) / Q000235:genetics* / Q000378:metabolism; D017856:Phosphotransferases (Phosphate Group Acceptor) / Q000235:genetics; D011730:Pyridoxal / Q000378:metabolism; D011731:Pyridoxal Kinase / Q000235:genetics / Q000378:metabolism; D011736:Pyridoxine / Q000031:analogs & derivatives / Q000378:metabolism / Q000494:pharmacology; D011743:Pyrimidines / Q000378:metabolism*; D013831:Thiamine / Q000378:metabolism; D013835:Thiamine Pyrophosphate / Q000096:biosynthesis*
chemical_list: D011743:Pyrimidines; D011730:Pyridoxal; C004675:4-deoxypyridoxine; D017853:Phosphotransferases (Alcohol Group Acceptor); D011731:Pyridoxal Kinase; C059599:hydroxymethylpyrimidine kinase; C051254:hydroxyethylthiazole kinase; D017856:Phosphotransferases (Phosphate Group Acceptor); C033532:phosphomethylpyrimidine kinase; C012068:toxopyrimidine; D011736:Pyridoxine; D013835:Thiamine Pyrophosphate; D013831:Thiamine