4ZM2: Antitoxin Phd From Phage P1 In Complex With Its Operator Dna Inverted Repeat In A Monoclinic Space Group

Conditional cooperativity is a common mechanism involved in transcriptional regulation of prokaryotic type II toxin-antitoxin operons and is intricately related to bacterial persistence. It allows the toxin component of a toxin-antitoxin module to act as a co-repressor at low doses of toxin as compared to antitoxin. When toxin level exceeds a certain threshold, however, the toxin becomes a de-repressor. Most antitoxins contain an intrinsically disordered region (IDR) that typically is involved in toxin neutralization and repressor complex formation. To address how the antitoxin IDR is involved in transcription regulation, we studied the phd-doc operon from bacteriophage P1. We provide evidence that the IDR of Phd provides an entropic barrier precluding full operon repression in the absence of Doc. Binding of Doc results in a cooperativity switch and consequent strong operon repression, enabling context-specific modulation of the regulatory process. Variations of this theme are likely to be a common mechanism in the autoregulation of bacterial operons that involve intrinsically disordered regions.
PDB ID: 4ZM2Download
MMDB ID: 139049
PDB Deposition Date: 2015/5/2
Updated in MMDB: 2016/07
Experimental Method:
x-ray diffraction
Resolution: 3.88  Å
Source Organism:
Similar Structures:
Biological Unit for 4ZM2: tetrameric; determined by author and by software (PISA)
Molecular Components in 4ZM2
Label Count Molecule
Proteins (2 molecules)
Antitoxin PHD(Gene symbol: phd)
Molecule annotation
Nucleotides(2 molecules)
DNA (5'-d(gp*cp*tp*tp*gp*tp*gp*tp*ap*cp*ap*cp*ap*t)-3')
Molecule annotation
DNA (5'-d(cp*ap*tp*gp*tp*gp*tp*ap*cp*ap*cp*ap*ap*g)-3')
Molecule annotation
* Click molecule labels to explore molecular sequence information.

Citing MMDB