4fxe | pdb_00004fxe

Crystal structure of the intact E. coli RelBE toxin-antitoxin complex

spinqualitylabelsall models 4fxe, resolution 2.75Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 4fxe is a 6 chain structure with sequence from Ecoli. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: SO4 Related: 3kha, 2kc8, 2kc9, 2k29 Gene: b1564, JW1556, relB (ECOLI), b1563, JW1555, relE (ECOLI) Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function [RELB_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. Seems to be a principal mediator of cell death in liquid media. [RELE_ECOLI] Toxic component of a toxin-antitoxin (TA) module. A sequence-specific, ribosome-dependent mRNA endoribonuclease that inhibits translation during amino acid starvation (the stringent response). Acts by cleaving mRNA with high codon specificity in the ribosomal A site between positions 2 and 3. The stop codon UAG is cleaved at a fast rate while UAA and UGA are cleaved with intermediate and slow rates. mRNA cleavage can also occur in the ribosomal E site after peptide release from peptidyl-tRNA in the P site as well as on free 30S subunits. Overexpression of RelE results in the inhibition of bacterial growth and a sharp decrease in colony-forming ability which is inhibited by the labile cognate antitoxin RelB. Overexpression also sharply increases persisters (cells that neither grow or die in presence of bactericidal agent and are largely responsible for high levels of biofilm tolerance to antimicrobials). Acts with RelB as a corepressor of relBE transcription. Seems to be a principal mediator of cell death in liquid media. Publication Abstract from PubMed The 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 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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