6G87
Flavonoid-responsive Regulator FrrA
Summary for 6G87
| Entry DOI | 10.2210/pdb6g87/pdb |
| Descriptor | TetR/AcrR family transcriptional regulator, 2-[N-CYCLOHEXYLAMINO]ETHANE SULFONIC ACID (2 entities in total) |
| Functional Keywords | flavonoids, repressor, tetr-family, transcription |
| Biological source | Bradyrhizobium diazoefficiens |
| Total number of polymer chains | 4 |
| Total formula weight | 96793.18 |
| Authors | Werner, N.,Hoppen, J.,Palm, G.,Werten, S.,Goettfert, M.,Hinrichs, W. (deposition date: 2018-04-07, release date: 2019-04-24, Last modification date: 2024-11-13) |
| Primary citation | Werner, N.,Werten, S.,Hoppen, J.,Palm, G.J.,Gottfert, M.,Hinrichs, W. The induction mechanism of the flavonoid-responsive regulator FrrA. Febs J., 2021 Cited by PubMed Abstract: Bradyrhizobium diazoefficiens, a bacterial symbiont of soybean and other leguminous plants, enters a nodulation-promoting genetic programme in the presence of host-produced flavonoids and related signalling compounds. Here, we describe the crystal structure of an isoflavonoid-responsive regulator (FrrA) from Bradyrhizobium, as well as cocrystal structures with inducing and noninducing ligands (genistein and naringenin, respectively). The structures reveal a TetR-like fold whose DNA-binding domain is capable of adopting a range of orientations. A single molecule of either genistein or naringenin is asymmetrically bound in a central cavity of the FrrA homodimer, mainly via C-H contacts to the π-system of the ligands. Strikingly, however, the interaction does not provoke any conformational changes in the repressor. Both the flexible positioning of the DNA-binding domain and the absence of structural change upon ligand binding are corroborated by small-angle X-ray scattering (SAXS) experiments in solution. Together with a model of the promoter-bound state of FrrA our results suggest that inducers act as a wedge, preventing the DNA-binding domains from moving close enough together to interact with successive positions of the major groove of the palindromic operator. PubMed: 34314575DOI: 10.1111/febs.16141 PDB entries with the same primary citation |
| Experimental method | X-RAY DIFFRACTION (2.92 Å) |
Structure validation
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