Ribosomes contain a number of modifications in rRNA, the function of which is unclear. Here we show--using proteomic analysis and dual fluorescence reporter in vivo assays--that m(2)G966 and m(5)C967 in 16S rRNA of Escherichia coli ribosomes are necessary for correct attenuation of tryptophan (trp) operon. Expression of trp operon is upregulated in the strain where RsmD and RsmB methyltransferases were deleted, which results in the lack of m(2)G966 and m(5)C967 modifications. The upregulation requires the trpL attenuator, but is independent of the promotor of trp operon, ribosome binding site of the trpE gene, which follows trp attenuator and even Trp codons in the trpL sequence. Suboptimal translation initiation efficiency in the rsmB/rsmD knockout strain is likely to cause a delay in translation relative to transcription which causes misregulation of attenuation control of trp operon.
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http://dx.doi.org/10.1038/srep03236 | DOI Listing |
Proc Natl Acad Sci U S A
January 2025
Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210.
The homo-dodecameric ring-shaped RNA binding attenuation protein (TRAP) from binds up to twelve tryptophan ligands (Trp) and becomes activated to bind a specific sequence in the 5' leader region of the operon mRNA, thereby downregulating biosynthesis of Trp. Thermodynamic measurements of Trp binding have revealed a range of cooperative behavior for different TRAP variants, even if the averaged apparent affinities for Trp have been found to be similar. Proximity between the ligand binding sites, and the ligand-coupled disorder-to-order transition has implicated nearest-neighbor interactions in cooperativity.
View Article and Find Full Text PDFJ Struct Biol X
December 2024
Ohio State Biochemistry Program, USA.
Cellular production of tryptophan is metabolically expensive and tightly regulated. The small zinc binding Anti-TRAP protein (AT), which is the product of the gene, is upregulated in response to accumulating levels of uncharged tRNA through a T-box antitermination mechanism. AT binds to the undecameric axially symmetric ring-shaped protein TRAP ( RNA Binding Attenuation Protein), thereby preventing it from binding to the leader RNA.
View Article and Find Full Text PDFAppl Environ Microbiol
July 2024
Department of Microbiology and Biotechnology, University of Hamburg, Hamburg, Germany.
Unlabelled: tarch tilization ystem (Sus)D-homologs are well known for their carbohydrate-binding capabilities and are part of the operon in microorganisms affiliated with the phylum Bacteroidota. Until now, SusD-like proteins have been characterized regarding their affinity toward natural polymers. In this study, three metagenomic SusD homologs (designated SusD1, SusD38489, and SusD70111) were identified and tested with respect to binding to natural and non-natural polymers.
View Article and Find Full Text PDFJ Microbiol Biol Educ
August 2024
Department of Biological and Chemical Sciences, College of Life Sciences, Thomas Jefferson University, Philadelphia, Pennsylvania, USA.
This paper presents two low-cost hands-on activities designed to enhance student understanding and address the pedagogical challenges faced by microbiology professors in teaching concepts related to cell structure and gene regulation. In the first activity, we used Shrinky Dinks and Jeopardy-style game questions to explore the differences between prokaryotic and eukaryotic cells. Students have to collect pieces and physically build their cell models.
View Article and Find Full Text PDFbioRxiv
May 2024
Department of Chemistry and Biochemistry, The Ohio State University.
Homotropic cooperativity is widespread in biological regulation. The homo-oligomeric ring-shaped RNA binding attenuation protein (TRAP) from bacillus binds multiple tryptophan ligands (Trp) and becomes activated to bind a specific sequence in the 5' leader region of the operon mRNA. Ligand-activated binding to this specific RNA sequence regulates downstream biosynthesis of Trp in a feedback loop.
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