Summary for 8A39
| Entry DOI | 10.2210/pdb8a39/pdb |
| Descriptor | DNA-binding transcriptional repressor of phenylacetic acid degradation, aryl-CoA responsive, GLYCEROL, SULFATE ION, ... (4 entities in total) |
| Functional Keywords | phenylacetic acid aerobic degradation, regulator, transcriptional repressor, transcription |
| Biological source | Escherichia coli W |
| Total number of polymer chains | 3 |
| Total formula weight | 106942.31 |
| Authors | Molina, R.,Alba-Perez, A.,Hermoso, J.A. (deposition date: 2022-06-07, release date: 2023-07-05, Last modification date: 2024-01-17) |
| Primary citation | Hernandez-Rocamora, V.M.,Molina, R.,Alba, A.,Carrasco-Lopez, C.,Rojas-Altuve, A.,Panjikar, S.,Medina, A.,Uson, I.,Alfonso, C.,Galan, B.,Rivas, G.,Hermoso, J.A.,Sanz, J.M. Structural characterization of PaaX, the main repressor of the phenylacetate degradation pathway in Escherichia coli W: A novel fold of transcription regulator proteins. Int.J.Biol.Macromol., 254:127935-127935, 2024 Cited by PubMed Abstract: PaaX is a transcriptional repressor of the phenylacetic acid (PAA) catabolic pathway, a central route for bacterial aerobic degradation of aromatic compounds. Induction of the route is achieved through the release of PaaX from its promoter sequences by the first compound of the pathway, phenylacetyl-coenzyme A (PA-CoA). We report the crystal structure of PaaX from Escherichia coli W. PaaX displays a novel type of fold for transcription regulators, showing a dimeric conformation where the monomers present a three-domain structure: an N-terminal winged helix-turn-helix domain, a dimerization domain similar to the Cas2 protein and a C-terminal domain without structural homologs. The domains are separated by a crevice amenable to harbour a PA-CoA molecule. The biophysical characterization of the protein in solution confirmed several hints predicted from the structure, i.e. its dimeric conformation, a modest importance of cysteines and a high dependence of solubility and thermostability on ionic strength. At a moderately acidic pH, the protein formed a stable folding intermediate with remaining α-helical structure, a disrupted tertiary structure and exposed hydrophobic patches. Our results provide valuable information to understand the stability and mechanism of PaaX and pave the way for further analysis of other regulators with similar structural configurations. PubMed: 37949283DOI: 10.1016/j.ijbiomac.2023.127935 PDB entries with the same primary citation |
| Experimental method | X-RAY DIFFRACTION (2.3 Å) |
Structure validation
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