RegulonDB RegulonDB 9.3:Regulon Page

TdcA DNA-binding transcriptional activator

Synonyms: TdcA
During anaerobiosis, TdcA participates in controlling genes (tdc operon) involved in transport and metabolism of threonine and serine [1, 2, 3]
TdcA belongs to the LysR family of transcriptional regulators, and like the other members of this family, it has a helix-turn-helix motif in the N-terminal domain for DNA binding [2]
Although interaction between TdcA and the regulatory region of the tdc operon has not been demonstrated, it has been suggested that TdcA recognizes and binds to an inverted repeat located upstream of the operon [1]
tdcA is the first gene in the tdcABCDEFG operon, which is autoactivated by TdcA. This operon is divergently transcribed with the tdcR gene, whose product also activates the transcription of the operon [4] TdcA probably interacts with TdcR to activate transcription [1] and they appear to function together with CRP and IHF, proteins that bend the DNA, for this activation [3]
A mutation in the tdcA gene of enterohemorrhagic Escherichia coli O157:H7 causes the expression of OmpA protein which is involved, among several other processes, in cellular adherence [5]
tdc: threonine dehydratase [6] Read more >

Transcription factor      
TF conformation(s):
Name Conformation Type TF-Effector Interaction Type Apo/Holo Conformation Evidence (Confirmed, Strong, Weak) References
TdcA     nd nd
Evolutionary Family: LysR
Sensing class: Sensing external and internal signals
Connectivity class: Local Regulator
Gene name: tdcA
  Genome position: 3266127-3267065
  Length: 939 bp / 312 aa
Operon name: tdcABCDEFG
TU(s) encoding the TF:
Transcription unit        Promoter

Regulated gene(s) tdcA, tdcB, tdcC, tdcD, tdcE, tdcF, tdcG
Multifun term(s) of regulated gene(s) MultiFun Term (List of genes associated to the multifun term)
amino acids (4)
threonine catabolism (3)
Transcription related (1)
activator (1)
operon (1)
Read more >
Regulated operon(s) tdcABCDEFG
First gene in the operon(s) tdcA
Simple and complex regulons CRP,FNR,IHF,TdcA,TdcR
Simple and complex regulatory phrases Regulatory phrase (List of promoters regulated by the phrase)

Transcription factor binding sites (TFBSs) arrangements       

  Functional conformation Function Promoter Sigma factor Central Rel-Pos Distance to first Gene Genes Sequence LeftPos RightPos Evidence (Confirmed, Strong, Weak) References
  TdcA activator tdcAp nd -177.0 -205.0 tdcA, tdcB, tdcC, tdcD, tdcE, tdcF, tdcG
3267263 3267277 [BCE], [GEA], [SM] [1]

Evolutionary conservation of regulatory elements    
     Note: Evolutionary conservation of regulatory interactions and promoters is limited to gammaproteobacteria.
Promoter-target gene evolutionary conservation


 [BCE] Binding of cellular extracts

 [GEA] Gene expression analysis

 [SM] Site mutation


 [1] Hagewood BT., Ganduri YL., Datta P., 1994, Functional analysis of the tdcABC promoter of Escherichia coli: roles of TdcA and TdcR., J Bacteriol. 176(20):6214-20

 [2] Ganduri YL., Sadda SR., Datta MW., Jambukeswaran RK., Datta P., 1993, TdcA, a transcriptional activator of the tdcABC operon of Escherichia coli, is a member of the LysR family of proteins., Mol Gen Genet. 240(3):395-402

 [3] Sawers G., 2001, A novel mechanism controls anaerobic and catabolite regulation of the Escherichia coli tdc operon., Mol Microbiol. 39(5):1285-98

 [4] Schweizer HP., Datta P., 1989, Identification and DNA sequence of tdcR, a positive regulatory gene of the tdc operon of Escherichia coli., Mol Gen Genet. 218(3):516-22

 [5] Torres AG., Kaper JB., 2003, Multiple elements controlling adherence of enterohemorrhagic Escherichia coli O157:H7 to HeLa cells., Infect Immun. 71(9):4985-95

 [6] Goss TJ., Datta P., 1984, Escherichia coli K-12 mutation that inactivates biodegradative threonine dehydratase by transposon Tn5 insertion., J Bacteriol. 158(3):826-31