7x7h
Crystal structure of Fructose regulator/Histidine phosphocarrier protein complex from Vibrio choleraeCrystal structure of Fructose regulator/Histidine phosphocarrier protein complex from Vibrio cholerae
Structural highlights
FunctionFRUR_VIBCH Regulates the expression of the fruBKA (fru) operon, which encodes proteins involved in the import and metabolism of fructose (PubMed:33476373, PubMed:33649152). In the absence of fructose 1-phosphate (F1P), binds to the promoter region of fruB, interferes with the binding of the RNA polymerase (RNAP) to the promoter and represses the expression of the operon (PubMed:33476373, PubMed:33649152). In the presence of F1P, activates the transcription of the fru operon by facilitating the binding of RNAP to the promoter (PubMed:33476373). Essential for the expression of the fru operon and thus for growth on fructose (PubMed:33476373).[1] [2] Publication Abstract from PubMedPhosphorylation state-dependent interactions of the phosphoenolpyruvate (PEP):carbohydrate phosphotransferase system (PTS) components with transcription factors play a key role in carbon catabolite repression (CCR) by glucose in bacteria. Glucose inhibits the PTS-dependent transport of fructose and is preferred over fructose in Vibrio cholerae, but the mechanism is unknown. We have recently shown that, contrary to Escherichia coli, the fructose-dependent transcriptional regulator FruR acts as an activator of the fru operon in V. cholerae and binding of the FruR-fructose 1-phosphate (F1P) complex to an operator facilitates RNA polymerase (RNAP) binding to the fru promoter. Here we show that, in the presence of glucose, dephosphorylated HPr, a general PTS component, binds to FruR. Whereas HPr does not affect DNA-binding affinity of FruR, regardless of the presence of F1P, it prevents the FruR-F1P complex from facilitating the binding of RNAP to the fru promoter. Structural and biochemical analyses of the FruR-HPr complex identify key residues responsible for the V. cholerae-specific FruR-HPr interaction not observed in E. coli. Finally, we reveal how the dephosphorylated HPr interacts with FruR in V. cholerae, whereas the phosphorylated HPr binds to CcpA, which is a global regulator of CCR in Bacillus subtilis and shows structural similarity to FruR. HPr prevents FruR-mediated facilitation of RNA polymerase binding to the fru promoter in Vibrio cholerae.,Yoon CK, Lee SH, Zhang J, Lee HY, Kim MK, Seok YJ Nucleic Acids Res. 2023 Jun 23;51(11):5432-5448. doi: 10.1093/nar/gkad220. PMID:36987873[3] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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