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4fxe
From Proteopedia
Crystal structure of the intact E. coli RelBE toxin-antitoxin complex
Structural highlights
FunctionRELB_ECOLI Antitoxin component of a toxin-antitoxin (TA) module. Counteracts the effect of RelE via direct protein-protein interaction, enabling the reversion of translation inhibition. Also acts as an autorepressor of relBE transcription. DNA-binding and repression is stronger when complexed with corepressor RelE. Increased transcription rate of relBE and activation of relE is consistent with a lower level of RelB in starved cells due to degradation of RelB by protease Lon.[1] [2] [3] [4] [5] Seems to be a principal mediator of cell death in liquid media.[6] [7] [8] [9] [10] Publication Abstract from PubMedThe bacterial relBE locus encodes a toxin-antitoxin complex in which the toxin, RelE, is capable of cleaving mRNA in the ribosomal A site cotranslationally. The antitoxin, RelB, both binds and inhibits RelE, and regulates transcription through operator binding and conditional cooperativity controlled by RelE. Here, we present the crystal structure of the intact Escherichia coli RelB2E2 complex at 2.8 A resolution, comprising both the RelB-inhibited RelE and the RelB dimerization domain that binds DNA. RelE and RelB associate into a V-shaped heterotetrameric complex with the ribbon-helix-helix (RHH) dimerization domain at the apex. Our structure supports a model in which relO is optimally bound by two adjacent RelB2E heterotrimeric units, and is not compatible with concomitant binding of two RelB2E2 heterotetramers. The results thus provide a firm basis for understanding the model of conditional cooperativity at the molecular level. The crystal structure of the intact E. coli RelBE toxin-antitoxin complex provides the structural basis for conditional cooperativity.,Boggild A, Sofos N, Andersen KR, Feddersen A, Easter AD, Passmore LA, Brodersen DE Structure. 2012 Oct 10;20(10):1641-8. doi: 10.1016/j.str.2012.08.017. Epub 2012, Sep 13. PMID:22981948[11] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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