A mutation in the putative CRP binding site of the dctA promoter of Salmonella enterica serovar Typhimurium enables growth with low orotate concentrations.
Can J Microbiol
; 68(10): 615-621, 2022 Oct 01.
Article
em En
| MEDLINE
| ID: mdl-35921682
ABSTRACT
Salmonella enterica and Escherichia coli use the inner membrane transporter DctA to import the pyrimidine biosynthetic pathway intermediate orotate from the environment. To study the regulation of dctA expression, we used an S. enterica serovar Typhimurium pyrimidine auxotroph to select a mutant that could grow in an otherwise nonpermissive culture medium containing glucose and a low concentration of orotate. Whole genome sequencing revealed a point mutation upstream of dctA in the putative cyclic AMP receptor protein (CRP) binding site. The CâT transition converted the least favourable base to the most favourable base for CRP-DNA affinity. A dctAlux transcriptional fusion confirmed that the mutant dctA promoter gained responsiveness to CRP even in the presence of glucose. Moreover, dctA expression was higher in the mutant than the wild type in the presence of alternative carbon sources that activate CRP.
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1
Coleções:
01-internacional
Contexto em Saúde:
3_ND
Base de dados:
MEDLINE
Assunto principal:
Salmonella typhimurium
/
Proteínas de Escherichia coli
Idioma:
En
Revista:
Can J Microbiol
Ano de publicação:
2022
Tipo de documento:
Article