2K29

Structure of the DBD domain of E. coli antitoxin RelB

Summary for 2K29

• Entry DOI: 10.2210/pdb2k29/pdb
• NMR Information: BMRB: 15691
• Descriptor: Antitoxin RelB (1 entity in total)
• Functional Keywords: relb, ribbon-helix-helix, antitoxin, repressor, stress response, transcription, transcription regulation
• Biological source: Escherichia coli
• Total number of polymer chains: 2
• Total formula weight: 12003.82

Authors

Li, G.,Zhang, Y.,Inouye, M.,Ikura, M. (deposition date: 2008-03-28, release date: 2008-04-22, Last modification date: 2024-05-08)

Primary citation

Li, G.Y.,Zhang, Y.,Inouye, M.,Ikura, M.
Structural mechanism of transcriptional autorepression of the Escherichia coli RelB/RelE antitoxin/toxin module.
J.Mol.Biol., 380:107-119, 2008

PubMed Abstract: The Escherichia coli chromosomal relBE operon encodes a toxin-antitoxin system, which is autoregulated by its protein products, RelB and RelE. RelB acts as a transcriptional repressor and RelE functions as a cofactor to enhance the repressor activity of RelB. Here, we present the NMR-derived structure of a RelB dimer and show that a RelB dimer recognizes a hexad repeat in the palindromic operator region through a ribbon-helix-helix motif. Our biochemical data show that two weakly associated RelB dimers bind to the adjacent repeats in the 3'-site of the operator (O(R)) at a moderate affinity (K(d), approximately 10(-5) M). However, in the presence of RelE, a RelB tetramer binds two distinct binding sites within the operator region, each with an enhanced affinity (K(d), approximately 10(-6) M for the low-affinity site, O(L), and 10(-8) M for the high-affinity site, O(R)). We propose that the enhanced affinity for the operator element is mediated by a cooperative DNA binding by a pair of RelB dimers and that the interaction between RelB dimers is strongly augmented by the presence of the cognate toxin RelE.

PubMed: 18501926
DOI: 10.1016/j.jmb.2008.04.039

Experimental method

SOLUTION NMR