Crystallisation and preliminary X-ray analysis of two variants of the Escherichia coli O157 PaaA2-ParE2 antitoxin-toxin complex

The paaR2-paaA2-parE2 operon is a three-component toxin-antitoxin (TA) module encoded in the genome of the human pathogen E. coli O157. The toxin (ParE2) and antitoxin (PaaA2) interact to form a non-toxic antitoxin-toxin complex. In this paper, the crystallisation and preliminary characterisation of two variants of the PaaA2-ParE2 antitoxin-toxin complex are described. Seleno-methionine derivative crystals of the full-length PaaA2-ParE2 antitoxin-toxin complex diffract to 2.8 Å and belong to space group P41212 (or P43212) with unit cell parameters a = b = 90.5 Å, c = 412.3 Å. In contrast, ParE2 and PaaA213-63, a truncated form of PaaA2 in which the first 12 N-terminal residues of the antitoxin have been deleted, form a hetero-dimer as evidenced by analytical gel filtration, dynamic light scattering, and small-angle X-ray scattering. Crystals of the PaaA213-63-ParE2 complex diffract to 2.7 Å and belong to space group P6122 (or P6522) with unit cell parameters a = b = 91.6 Å, c = 185.6 Å.

Jaar van publicatie:2014

Trefwoorden:structural biology, bacterial stress response, X-ray crystallography, toxin-antitoxin module, persistence