Regulation of Tryptophan Operon Expression in the Archaeon Methanothermobacter thermautotrophicus
Open Access
- 15 September 2005
- journal article
- research article
- Published by American Society for Microbiology in Journal of Bacteriology
- Vol. 187 (18), 6419-6429
- https://doi.org/10.1128/jb.187.18.6419-6429.2005
Abstract
Conserved trp genes encode enzymes that catalyze tryptophan biosynthesis in all three biological domains, and studies of their expression in Bacteria and eukaryotes have revealed a variety of different regulatory mechanisms. The results reported here provide the first detailed description of an archaeal trp gene regulatory system. We have established that the trpEGCFBAD operon in Methanothermobacter thermautotrophicus is transcribed divergently from a gene (designated trpY ) that encodes a tryptophan-sensitive transcription regulator. TrpY binds to TRP box sequences (consensus, TGTACA) located in the overlapping promoter regions between trpY and trpE , inhibiting trpY transcription in the absence of tryptophan and both trpY and trpEGCFBAD transcription in the presence of tryptophan. TrpY apparently inhibits trpY transcription by blocking RNA polymerase access to the site of trpY transcription initiation and represses trpEGCFBAD transcription by preventing TATA box binding protein (TBP) binding to the TATA box sequence. Given that residue 2 (W2) is the only tryptophan in TrpY and in TrpY homologues in other Euryarchaea and that there is only one tryptophan codon in the entire trpEGCFBAD operon ( trpB encodes W175), expression of the trp operon may also be regulated in vivo by the supply of charged tRNA Trp available to translate the second codon of the trpY mRNA.Keywords
This publication has 57 references indexed in Scilit:
- Evidence of selection for low cognate amino acid bias in amino acid biosynthetic enzymesMolecular Microbiology, 2005
- Transcription by Methanothermobacter thermautotrophicus RNA Polymerase In Vitro Releases Archaeal Transcription Factor B but Not TATA-Box Binding Protein from the Template DNAJournal of Bacteriology, 2004
- A Novel Tryptophan Synthase β-Subunit from the HyperthermophileThermotoga maritimaJournal of Biological Chemistry, 2002
- Events during Initiation of Archaeal Transcription: Open Complex Formation and DNA-Protein InteractionsJournal of Bacteriology, 2001
- An Lrp-like Transcriptional Regulator from the ArchaeonPyrococcus furiosus Is Negatively AutoregulatedJournal of Biological Chemistry, 2000
- Mechanism of Autoregulation by an Archaeal Transcriptional RepressorPublished by Elsevier ,2000
- Gleaning non-trivial structural, functional and evolutionary information about proteins by iterative database searchesJournal of Molecular Biology, 1999
- In vivoandin vitroStudies of TrpR-DNA InteractionsJournal of Molecular Biology, 1996
- Escherichia coli RNA polymerase and trp repressor interaction with the promoter-operator region of the tryptophan operon of Salmonella typhimuriumJournal of Molecular Biology, 1980
- Interaction of the trp repressor and RNA polymerase with the trp operonJournal of Molecular Biology, 1975