Identification and characterization of an operon in Salmonella typhimurium involved in thiamine biosynthesis.

AUTOR(ES)

Petersen, L A

RESUMO

Thiamine pyrophosphate (TPP) is synthesized de novo in Salmonella typhimurium and is a required cofactor for many enzymes in the cell. Five kinase activities have been implicated in TPP synthesis, which involves joining a 4-methyl-5-(beta-hydroxyethyl)thiazole (THZ) moiety and a 4-amino-5-hydroxymethyl-2-methylpyrimidine (HMP) moiety. We report here identification of a 2-gene operon involved in thiamine biosynthesis and present evidence that the genes in this operon, thiMD, encode two previously identified kinases, THZ kinase and HMP phosphate (HMP-P) kinase, respectively. We further show that this operon belongs to the growing class of genes involved in TPP synthesis that are transcriptionally regulated by TPP. Our data are consistent with ThiM being a salvage enzyme and ThiD being a biosynthetic enzyme involved in TPP synthesis, as previously suggested.

Documentos Relacionados

• Characterization of the Bacillus subtilis thiC operon involved in thiamine biosynthesis.
• apbA, a new genetic locus involved in thiamine biosynthesis in Salmonella typhimurium.
• Identification of an operon involved in sulfolipid biosynthesis in Rhodobacter sphaeroides.
• Cloning and sequencing of the Escherichia coli chlEN operon involved in molybdopterin biosynthesis.
• Characterization of thiI, a new gene involved in thiazole biosynthesis in Salmonella typhimurium.