1z3e
From Proteopedia
Crystal Structure of Spx in Complex with the C-terminal Domain of the RNA Polymerase Alpha Subunit
Structural highlights
Function[SPX_BACSU] Interferes with activator-stimulated transcription by interaction with the RNA polymerase alpha-CTD. May function to globally reduce transcription of genes involved in growth- and development-promoting processes and to increase transcription of genes involved in thiol homeostasis, during periods of extreme stress. Negatively affects competence and sporulation. Its degradation by the MecA/ClpXP complex is needed for competence development.[1] [2] [RPOA_BACSU] DNA-dependent RNA polymerase catalyzes the transcription of DNA into RNA using the four ribonucleoside triphosphates as substrates. Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedSpx, a global transcription regulator in Bacillus subtilis, interacts with the C-terminal domain of the alpha subunit (alphaCTD) of RNA polymerase to control gene expression under conditions of disulfide stress, which is sensed by disulfide bond formation between Spx residues C10 and C13. Here, we describe the crystal structure of the B. subtilis alphaCTD bound to oxidized Spx. Analysis of the complex reveals interactions between three regions of "anti-alpha" Spx and helix alpha1 and the "261" determinant of alphaCTD. The former contact could disrupt the interaction between alphaCTD and activator proteins or alter the DNA-bound conformation of alphaCTD, thereby repressing activator-stimulated transcription. Binding to the 261 determinant would prevent interaction between alphaCTD and region 4 of sigma(A). Intriguingly, the Spx disulfide bond is far from the alphaCTD-Spx interface, suggesting that Spx regulates transcription allosterically or through the redox-dependent creation or destruction of binding sites for additional components of the transcription machinery. Crystal structure of the Bacillus subtilis anti-alpha, global transcriptional regulator, Spx, in complex with the alpha C-terminal domain of RNA polymerase.,Newberry KJ, Nakano S, Zuber P, Brennan RG Proc Natl Acad Sci U S A. 2005 Nov 1;102(44):15839-44. Epub 2005 Oct 25. PMID:16249335[3] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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