Structural and functional characterization of Escherichia coli toxin-antitoxin complex DinJ-YafQ.

ABSTRACT: Toxin YafQ functions as a ribonuclease in the dinJ-yafQ toxin-antitoxin system of Escherichia coli. Antitoxin DinJ neutralizes YafQ-mediated toxicity by forming a stable protein complex. Here, crystal structures of the (DinJ)2-(YafQ)2 complex and the isolated YafQ toxin have been determined. The structure of the heterotetrameric complex (DinJ)2-(YafQ)2 revealed that the N-terminal region of DinJ folds into a ribbon-helix-helix motif and dimerizes for DNA recognition, and the C-terminal portion of each DinJ exclusively wraps around a YafQ molecule. Upon incorporation into the heterotetrameric complex, a conformational change of YafQ in close proximity to the catalytic site of the typical microbial ribonuclease fold was observed and validated. Mutagenesis experiments revealed that a DinJ mut

SUBMITTER: Liang Y 

PROVIDER: S-EPMC4110321 | biostudies-literature | 2014 Jul

REPOSITORIES: biostudies-literature