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Crystallization and preliminary X‐ray analysis of two variants of the Escherichia coli O157 ParE2–PaaA2 toxin–antitoxin complex
Author(s) -
Sterckx Yann G. J.,
Haesaerts Sarah,
Van Melderen Laurence,
Loris Remy
Publication year - 2014
Publication title -
acta crystallographica section f
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.572
H-Index - 37
ISSN - 2053-230X
DOI - 10.1107/s2053230x1401749x
Subject(s) - antitoxin , escherichia coli , toxin , operon , microbiology and biotechnology , biology , chemistry , crystallography , biochemistry , gene
The paaR2 – paaA2 – parE2 operon is a three‐component toxin–antitoxin module encoded in the genome of the human pathogen Escherichia coli O157. The toxin (ParE2) and antitoxin (PaaA2) interact to form a nontoxic toxin–antitoxin complex. In this paper, the crystallization and preliminary characterization of two variants of the ParE2–PaaA2 toxin–antitoxin complex are described. Selenomethionine‐derivative crystals of the full‐length ParE2–PaaA2 toxin–antitoxin complex diffracted to 2.8 Å resolution and belonged to space group P 4 1 2 1 2 (or P 4 3 2 1 2), with unit‐cell parameters a = b = 90.5, c = 412.3 Å. It was previously reported that the full‐length ParE2–PaaA2 toxin–antitoxin complex forms a higher‐order oligomer. In contrast, ParE2 and PaaA2 13–63 , a truncated form of PaaA2 in which the first 12 N‐terminal residues of the antitoxin have been deleted, form a heterodimer as shown by analytical gel filtration, dynamic light scattering and small‐angle X‐ray scattering. Crystals of the PaaA2 13–63 –ParE2 complex diffracted to 2.7 Å resolution and belonged to space group P 6 1 22 (or P 6 5 22), with unit‐cell parameters a = b = 91.6, c = 185.6 Å.