6KYT

The structure of the M. tb toxin MazEF-mt1 complex

Summary for 6KYT

• Entry DOI: 10.2210/pdb6kyt/pdb
• Descriptor: Endoribonuclease MazF9, Antitoxin MazE9 (3 entities in total)
• Functional Keywords: rna endonlease, protein engineering, toxin
• Biological source: Mycobacterium tuberculosis H37Rv; More
• Total number of polymer chains: 12
• Total formula weight: 141972.33

Authors

Xie, W.,Chen, R.,Zhou, J. (deposition date: 2019-09-20, release date: 2020-08-05, Last modification date: 2023-11-22)

Primary citation

Chen, R.,Zhou, J.,Sun, R.,Du, C.,Xie, W.
Conserved Conformational Changes in the Regulation ofMycobacterium tuberculosisMazEF-mt1.
Acs Infect Dis., 6:1783-1795, 2020

PubMed Abstract: Toxin-antitoxin (TA) systems, which regulate many important cellular processes, are abundantly present in prokaryotic organisms. MazEF is a common type of TA system implicated in the formation of "persisters cells" of the pathogen , which contains 10 such systems. However, the exact function and inhibition mode of each MazF protein are not quite understood. Here, we report four high-resolution crystal structures of MazF-mt1 in various forms, including one in complex with MazE-mt1. The toxin displayed two unique interlocked loops that allow the formation of a tight dimer. These loops would open upon interacting with the MazE-mt1 antitoxin mediated by the last two helices of MazE-mt1. With our structure-based design, a mutant that could bind to the antitoxin with an enhanced affinity was produced. Combined crystallographic and biochemical studies further revealed that the binding affinity of MazE-mt1 to MazF-mt1 was mainly attributed to its α3 helical region, while the terminal helix η1 contributes very little or even negatively to the association of the pair, in stark contrast to the MazEF-mt9 system. This study provides structural insight into the binding mode and the inhibition mechanism of the MazE/F-mt1 TA pair, which may reflect the functional differences between different TA systems.

PubMed: 32485099
DOI: 10.1021/acsinfecdis.0c00048

Experimental method

X-RAY DIFFRACTION (2.00101167265 Å)