Mechanisms of neutralization of toxSAS from toxin-antitoxin modules.

Toxic small alarmone synthetase (toxSAS) enzymes constitute a family of bacterial effectors present in toxin-antitoxin and secretion systems. toxSASs act through either translation inhibition mediated by pyrophosphorylation of transfer RNA (tRNA) CCA ends or synthesis of the toxic alarmone adenosine pentaphosphate ((pp)pApp) and adenosine triphosphate (ATP) depletion, exemplified by FaRel2 and FaRel, respectively. However, structural bases of toxSAS neutralization are missing.

The Escherichia coli RnlA-RnlB toxin-antitoxin complex: production, characterization and crystallization.

The Escherichia coli rnlAB operon encodes a toxin-antitoxin module that is involved in protection against infection by bacteriophage T4. The full-length RnlA-RnlB toxin-antitoxin complex as well as the toxin RnlA were purified to homogeneity and crystallized. When the affinity tag is placed on RnlA, RnlB is largely lost during purification and the resulting crystals exclusively comprise RnlA.