7ZG5
The crystal structure of Salmonella TacAT3-DNA complex
Summary for 7ZG5
| Entry DOI | 10.2210/pdb7zg5/pdb |
| Descriptor | Acetyltransferase, DUF1778 domain-containing protein, tacAT3 DNA operator, ... (9 entities in total) |
| Functional Keywords | toxin-antitoxin system, salmonella, acetyltransferase, conditional cooperativity, toxin |
| Biological source | Salmonella enterica subsp. enterica serovar Typhimurium More |
| Total number of polymer chains | 6 |
| Total formula weight | 68539.94 |
| Authors | Grabe, G.J.,Morgan, R.M.L.,Helaine, S. (deposition date: 2022-04-01, release date: 2023-10-11, Last modification date: 2024-04-10) |
| Primary citation | Grabe, G.J.,Giorgio, R.T.,Wieczor, M.,Gollan, B.,Sargen, M.,Orozco, M.,Hare, S.A.,Helaine, S. Molecular stripping underpins derepression of a toxin-antitoxin system. Nat.Struct.Mol.Biol., 2024 Cited by PubMed Abstract: Transcription factors control gene expression; among these, transcriptional repressors must liberate the promoter for derepression to occur. Toxin-antitoxin (TA) modules are bacterial elements that autoregulate their transcription by binding the promoter in a T:A ratio-dependent manner, known as conditional cooperativity. The molecular basis of how excess toxin triggers derepression has remained elusive, largely because monitoring the rearrangement of promoter-repressor complexes, which underpin derepression, is challenging. Here, we dissect the autoregulation of the Salmonella enterica tacAT3 module. Using a combination of assays targeting DNA binding and promoter activity, as well as structural characterization, we determine the essential TA and DNA elements required to control transcription, and we reconstitute a repression-to-derepression path. We demonstrate that excess toxin triggers molecular stripping of the repressor complex off the DNA through multiple allosteric changes causing DNA distortion and ultimately leading to derepression. Thus, our work provides important insight into the mechanisms underlying conditional cooperativity. PubMed: 38538913DOI: 10.1038/s41594-024-01253-2 PDB entries with the same primary citation |
| Experimental method | X-RAY DIFFRACTION (2 Å) |
Structure validation
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