6g8h

Flavonoid-responsive Regulator FrrA in complex with (R,S)-Naringenin

spinqualitylabelsall models 6g8h, resolution 2.60Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 6g8h is a 4 chain structure. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: CWE, NAR, NHE NonStd Res: MSE Related: 6g87 Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Publication Abstract from PubMed Previous microarray analyses revealed that in Bradyrhizobium japonicum, about 100 genes are induced by genistein, an isoflavonoid secreted by soybean. This includes the three genes freC, freA, and freB (systematic designations bll4319, bll4320, and bll4321), which are likely to form a genistein-, daidzein-, and coumestrol-inducible operon and to encode a multidrug efflux system. Upstream of freCAB and in the opposite orientation, FrrA (systematic designation Blr4322), which has similarity to TetR-type regulators, is encoded. A deletion of frrA leads to increased expression of freB in the absence of an inducer. We identified the correct translational start codon of frrA and showed that the gene is inducible by genistein and daidzein. The protein, which was heterologously expressed and purified from Escherichia coli, binds to two palindrome-like DNA elements (operator A and operator B), which are located in the intergenic region between freC and frrA. The replacement of several nucleotides or the insertion of additional spacer nucleotides prevented binding. Binding of FrrA was also affected by the addition of genistein. By mapping the transcription start sites, we found that operator A covers the transcriptional start site of freC and operator B is probably located between the -35 regions of the two divergently oriented genes. Operator A seems to be conserved in a few similar gene constellations in other proteobacteria. Our data indicate that in B. japonicum, besides NodD1 (the LysR family) and NodVW (a two-component response regulator), a third regulator type (a TetR family member) which responds to the plant signal molecules genistein and daidzein exists. Characterization of the flavonoid-responsive regulator FrrA and its binding sites.,Wenzel M, Lang K, Gunther T, Bhandari A, Weiss A, Lulchev P, Szentgyorgyi E, Kranzusch B, Gottfert M J Bacteriol. 2012 May;194(9):2363-70. doi: 10.1128/JB.06567-11. Epub 2012 Mar 2. PMID:22389485 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Tetracycline repressor protein 3D structures Transcriptional activator 3D structures

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