کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
1931481 | 1050554 | 2010 | 6 صفحه PDF | دانلود رایگان |
![عکس صفحه اول مقاله: The structural mechanism of the inhibition of archaeal RelE toxin by its cognate RelB antitoxin The structural mechanism of the inhibition of archaeal RelE toxin by its cognate RelB antitoxin](/preview/png/1931481.png)
The archaeal toxin, aRelE, in the hyperthermophilic archaeon Pyrococcus horikoshii OT3 inhibits protein synthesis, whereas its cognate antitoxin, aRelB, neutralizes aRelE activity by forming a non-toxic complex, aRelB–aRelE. The structural mechanism whereby aRelB neutralizes aRelE activity was examined by biochemical and biophysical analyses. Overexpression of aRelB with an aRelE mutant (ΔC6), in which the C-terminal residues critical for aRelE activity were deleted, in Escherichia coli allowed a stable complex, aRelB–ΔC6, to be purified. Isothermal titration of aRelE or ΔC6 with aRelB indicated that the association constant (Ka) of wild-type aRelB–aRelE is similar to that of aRelB–ΔC6, demonstrating that aRelB makes little contact with the C-terminal active site of aRelE. Overexpression of deletion mutants of aRelB with aRelE indicated that either the N-terminal (pos. 1–27) or C-terminal (pos. 50–67) fragment of aRelB is sufficient to counteract the toxicity of aRelE in E. coli cells and the second α-helix (α2) in aRelB plays a critical role in forming a stable complex with aRelE. The present results demonstrate that aRelB, as expected from its X-ray structure, precludes aRelE from entering the ribosome, wrapping around the molecular surface of aRelE.
Research highlights
► An aRelB–aRelE complex is the RelB–RelE homologue in Pyrococcus horikoshii.
► The structural mechanism whereby aRelB neutralizes aRelE activity was examined.
► aRelB does not target the C-terminal active site of aRelE.
► aRelB precludes aRelE from entering the ribosome, wrapping around aRelE.
Journal: Biochemical and Biophysical Research Communications - Volume 400, Issue 3, 24 September 2010, Pages 346–351