Characterization of the Bacillus subtilis thiC operon involved in thiamine biosynthesis.
The characterization of a three-gene operon (the thiC operon) at 331 min, which is involved in thiamine biosynthesis in Bacillus subtilis, is described. The first gene in the operon is homologous to transcription activators in the lysR family. The second and third genes (thiK and thiC) have been subcloned and overexpressed in Escherichia coli. ThiK (30 kDa) catalyzes the phosphorylation of 4-methyl-5-(beta-hydroxyethyl)thiazole. ThiC (27 kDa) catalyzes the substitution of the pyrophosphate of 2-methyl-4-amino-5-hydroxymethylpyrimidine pyrophosphate by 4-methyl-5-(beta-hydroxyethyl)thiazole phosphate to yield thiamine phosphate. Transcription of the thiC operon is not regulated by thiamine or 2-methyl-4-amino-5-hydroxymethylpyrimidine and is only slightly repressed by 4-methyl-5-(beta-hydroxyethyl)thiazole.
Zhang
Y
Y
Department of Chemistry, Cornell University, Ithaca, New York 14853, USA.
Taylor
S V
SV
Chiu
H J
HJ
Begley
T P
TP
D000595:Amino Acid Sequence; D001412:Bacillus subtilis / Q000235:genetics* / Q000378:metabolism; D001426:Bacterial Proteins / Q000096:biosynthesis* / Q000737:chemistry / Q000235:genetics; D001483:Base Sequence; D003001:Cloning, Molecular; D017931:DNA Primers; D004926:Escherichia coli; D015964:Gene Expression Regulation, Bacterial; D008969:Molecular Sequence Data; D009876:Operon; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000737:chemistry; D017386:Sequence Homology, Amino Acid; D013831:Thiamine / Q000096:biosynthesis*; D015534:Trans-Activators / Q000096:biosynthesis / Q000235:genetics; D014158:Transcription, Genetic
D001426:Bacterial Proteins; D017931:DNA Primers; D011994:Recombinant Proteins; C105797:ThiC protein, Bacteria; D015534:Trans-Activators; D013831:Thiamine