title: Structural basis of mRNA recognition and cleavage by toxin MazF and its regulation by antitoxin MazE in Bacillus subtilis.
abstract: MazF 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.
authors.affiliation: Structural Biology Program, Memorial Sloan-Kettering Cancer Center, New York, NY 10065, USA.
authors.forename: Dhirendra K
authors.initials: DK
authors.lastname: Simanshu
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Yamaguchi
authors.forename: Jung-Ho
authors.initials: JH
authors.lastname: Park
authors.forename: Masayori
authors.initials: M
authors.lastname: Inouye
authors.forename: Dinshaw J
authors.initials: DJ
authors.lastname: Patel
mesh_terms: D000992:Antitoxins / Q000737:chemistry; D001412:Bacillus subtilis / Q000737:chemistry*; D018360:Crystallography, X-Ray; D004268:DNA-Binding Proteins / Q000737:chemistry*; D004722:Endoribonucleases / Q000737:chemistry*; D004926:Escherichia coli / Q000737:chemistry; D029968:Escherichia coli Proteins / Q000737:chemistry*; D009154:Mutation; D012333:RNA, Messenger / Q000737:chemistry*; D013329:Structure-Activity Relationship; D013379:Substrate Specificity
chemical_list: D000992:Antitoxins; D004268:DNA-Binding Proteins; D029968:Escherichia coli Proteins; C422954:MazE protein, E coli; C422955:MazF protein, E coli; D012333:RNA, Messenger; D004722:Endoribonucleases