Designed by: Lukas Rieder   Group: iGEM16_NAWI-Graz   (2016-09-15)

mazE antitoxin

This sequence encodes for the mazE protein. This protein is the antitoxin for the mazF toxin (BBa_K2142003). Together the parts form the mazEF system which can be used as selectable marker. This part is not a standard BioBrick and can be found in BBa_K2142000

This CDS is obtained from E. coli



Vilnius-Lithuania iGEM 2020 project FlavoFlowincludes three goals towards looking for Flavobacterium disease-related problems’ solutions. The project includes creating a rapid detection kit, based on HDA and LFA, developing an implement for treating a disease, and introducing the foundation of edible vaccines. This part was used for the second goal- treatment - of the project FlavoFlow.


Toxin-antitoxin (TA) system is abundant in all bacteria. The TA presence in bacteria is as a response to stress conditions1. The comprehensively investigated system is mazEF in Escherichia Coli2,3. These kinds of systems regulate cell death and survival. During cell growth, the toxin is cohered with antitoxin4. The antitoxin degrades and detaches from a toxin in the presence of stress conditions. The mazEF system belongs to type II toxin and antitoxin interaction. The most common toxins are ribonucleases in type II TA5.

The MazE is the antidote element in mazEF heterocomplex. This homodimer sits between two MazF homodimers. The MazE forms an intertwined β barrel with two extended C-terminal segments that interact with the MazF homodimer. The N-terminal globular region contributes two pairs of β strands connected by a short α helix to an intimate barrel-like structure with a single hydrophobic core6. The MazE monomer can recognize MazF homodimer via four surface sites.


  1. Christensen-Dalsgaard, M. & Gerdes, K. Translation affects YoeB and MazF messenger RNA interferase activities by different mechanisms. Nucleic Acids Research 36, 6472–6481 (2008).
  2. Nigam, A., Ziv, T., Oron-Gottesman, A. & Engelberg-Kulka, H. Stress-Induced MazF-Mediated Proteins in Escherichia coli. mBio 10, e00340-19, /mbio/10/2/mBio.00340-19.atom (2019).
  3. Culviner, P. H. & Laub, M. T. Global Analysis of the E. coli Toxin MazF Reveals Widespread Cleavage of mRNA and the Inhibition of rRNA Maturation and Ribosome Biogenesis. Molecular Cell 70, 868-880.e10 (2018).
  4. Cho, J., Carr, A. N., Whitworth, L., Johnson, B. & Wilson, K. S. MazEF toxin-antitoxin proteins alter Escherichia coli cell morphology and infrastructure during persister formation and regrowth. Microbiology 163, 308–321 (2017).
  5. Mets, T. et al. Fragmentation of Escherichia coli mRNA by MazF and MqsR. Biochimie 156, 79–91 (2019).
  6. Kamada, K., Hanaoka, F. & Burley, S. K. Crystal Structure of the MazE/MazF Complex: Molecular Bases of Antidote-Toxin Recognition. Molecular Cell 10.