Heat-stable and heat-labile thymidylate synthases B of Bacillus subtilis: comparison of the nucleotide and amino acid sequences.
Bacillus subtilis 168 is known to possess two thymidylate synthase (TSase; EC 2.1.1.45) genes: thyA and thyB. thyB encodes a thermosensitive TSase (inactivated at 46 degrees C) which, in wild-type cells, accounts for only 5-8% of the total cellular TSase activity. In order to investigate the thermal lability of TSaseB we have analyzed the thyB genes of B. subtilis 168 and of an unrelated strain B. subtilis ATCC6633, which is shown here to have a temperature-resistant TSaseB. This conclusion is supported by the frequency of appearance of spontaneous Thy- mutants at 37 degrees C and 46 degrees C, and by the analysis of clones containing the thyB genes from the two strains. The nucleotide sequences of these two thyB genes were compared.
Montorsi
M
M
Lepetit Research Center, Gerenzano, Italy.
Lorenzetti
R
R
D000595:Amino Acid Sequence; D001412:Bacillus subtilis / Q000201:enzymology*; D001483:Base Sequence; D003001:Cloning, Molecular; D004269:DNA, Bacterial; D004795:Enzyme Stability; D006358:Hot Temperature; D008969:Molecular Sequence Data; D009154:Mutation; D010641:Phenotype; D015183:Restriction Mapping; D013940:Thymidylate Synthase / Q000737:chemistry*
D004269:DNA, Bacterial; D013940:Thymidylate Synthase