4me7
From Proteopedia
Crystal structure of Bacillus subtilis toxin MazF in complex with cognate antitoxin MazE
Structural highlights
Function[ENDOA_BACSU] Toxic component of a toxin-antitoxin (TA) module. Has specificity for UACAU sequences, claving after the first U and yielding cleavage products with 3' phosphate and 5' hydroxyl groups. Overexpression is toxic for cell growth, probably by inhibiting protein synthesis through the cleavage of single-stranded RNA. The toxicity is reversed by the antitoxin EndoAI. Toxin activity cannot be inhibited by MazE from E.coli.[1] [2] [ENDAI_BACSU] Antitoxin component of a toxin-antitoxin (TA) module. Antitoxin that directly inhibits activity of EndoA in vitro. Upon expression in E.coli counteracts inhibitory effect of mRNA interferase EndoA.[3] [4] Publication Abstract from PubMedMazF is an mRNA interferase, which, upon activation during stress conditions, cleaves mRNAs in a sequence-specific manner, resulting in cellular growth arrest. During normal growth conditions, the MazF toxin is inactivated through binding to its cognate antitoxin, MazE. How MazF specifically recognizes its mRNA target and carries out cleavage and how the formation of the MazE-MazF complex inactivates MazF remain unclear. We present crystal structures of MazF in complex with mRNA substrate and antitoxin MazE in Bacillus subtilis. The structure of MazF in complex with uncleavable UUdUACAUAA RNA substrate defines the molecular basis underlying the sequence-specific recognition of UACAU and the role of residues involved in the cleavage through site-specific mutational studies. The structure of the heterohexameric (MazF)2-(MazE)2-(MazF)2 complex in Bacillus subtilis, supplemented by mutational data, demonstrates that the positioning of the C-terminal helical segment of MazE within the RNA-binding channel of the MazF dimer prevents mRNA binding and cleavage by MazF. Structural Basis of mRNA Recognition and Cleavage by Toxin MazF and Its Regulation by Antitoxin MazE in Bacillus subtilis.,Simanshu DK, Yamaguchi Y, Park JH, Inouye M, Patel DJ Mol Cell. 2013 Oct 8. pii: S1097-2765(13)00676-X. doi:, 10.1016/j.molcel.2013.09.006. PMID:24120662[5] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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