title: Substrate Recognition and Activity Regulation of the Escherichia coli mRNA Endonuclease MazF.
abstract: Escherichia coli MazF (EcMazF) is the archetype of a large family of ribonucleases involved in bacterial stress response. The crystal structure of EcMazF in complex with a 7-nucleotide substrate mimic explains the relaxed substrate specificity of the E. coli enzyme relative to its Bacillus subtilis counterpart and provides a framework for rationalizing specificity in this enzyme family. In contrast to a conserved mode of substrate recognition and a conserved active site, regulation of enzymatic activity by the antitoxin EcMazE diverges from its B. subtilis homolog. Central in this regulation is an EcMazE-induced double conformational change as follows: a rearrangement of a crucial active site loop and a relative rotation of the two monomers in the EcMazF dimer. Both are induced by the C-terminal residues Asp-78-Trp-82 of EcMazE, which are also responsible for strong negative cooperativity in EcMazE-EcMazF binding. This situation shows unexpected parallels to the regulation of the F-plasmid CcdB activity by CcdA and further supports a common ancestor despite the different activities of the MazF and CcdB toxins. In addition, we pinpoint the origin of the lack of activity of the E24A point mutant of EcMazF in its inability to support the substrate binding-competent conformation of EcMazF.
authors.affiliation: From the Structural Biology Brussels, Department of Biotechnology, Vrije Universiteit Brussel, Pleinlaan 2, B-1050 Brussels, Belgium, the Structural Biology Research Center, VIB, Pleinlaan 2, B-1050 Brussels, Belgium.
authors.forename: Valentina
authors.initials: V
authors.lastname: Zorzini
authors.affiliation: the Faculty of Chemistry and Chemical Technology, University of Ljubljana, Večna pot 113, 1000 Ljubljana, Slovenia, and.
authors.forename: Andrej
authors.initials: A
authors.lastname: Mernik
authors.affiliation: the Faculty of Chemistry and Chemical Technology, University of Ljubljana, Večna pot 113, 1000 Ljubljana, Slovenia, and.
authors.forename: Jurij
authors.initials: J
authors.lastname: Lah
authors.affiliation: From the Structural Biology Brussels, Department of Biotechnology, Vrije Universiteit Brussel, Pleinlaan 2, B-1050 Brussels, Belgium, the Structural Biology Research Center, VIB, Pleinlaan 2, B-1050 Brussels, Belgium.
authors.forename: Yann G J
authors.initials: YG
authors.lastname: Sterckx
authors.affiliation: From the Structural Biology Brussels, Department of Biotechnology, Vrije Universiteit Brussel, Pleinlaan 2, B-1050 Brussels, Belgium, the Structural Biology Research Center, VIB, Pleinlaan 2, B-1050 Brussels, Belgium.
authors.forename: Natalie
authors.initials: N
authors.lastname: De Jonge
authors.affiliation: From the Structural Biology Brussels, Department of Biotechnology, Vrije Universiteit Brussel, Pleinlaan 2, B-1050 Brussels, Belgium, the Biologie Structurale et Biophysique, Université Libre de Bruxelles, Rue des Professeurs Jeener et Brachet 12, 6041 B-Gosselies, Belgium.
authors.forename: Abel
authors.initials: A
authors.lastname: Garcia-Pino
authors.affiliation: From the Structural Biology Brussels, Department of Biotechnology, Vrije Universiteit Brussel, Pleinlaan 2, B-1050 Brussels, Belgium, the Structural Biology Research Center, VIB, Pleinlaan 2, B-1050 Brussels, Belgium.
authors.forename: Henri
authors.initials: H
authors.lastname: De Greve
authors.affiliation: From the Structural Biology Brussels, Department of Biotechnology, Vrije Universiteit Brussel, Pleinlaan 2, B-1050 Brussels, Belgium, the Structural Biology Research Center, VIB, Pleinlaan 2, B-1050 Brussels, Belgium.
authors.forename: Wim
authors.initials: W
authors.lastname: Versées
authors.affiliation: From the Structural Biology Brussels, Department of Biotechnology, Vrije Universiteit Brussel, Pleinlaan 2, B-1050 Brussels, Belgium, the Structural Biology Research Center, VIB, Pleinlaan 2, B-1050 Brussels, Belgium, reloris@vub.ac.be.
authors.forename: Remy
authors.initials: R
authors.lastname: Loris
mesh_terms: D001412:Bacillus subtilis / Q000201:enzymology; D001426:Bacterial Proteins / Q000737:chemistry / Q000378:metabolism; D020134:Catalytic Domain / Q000235:genetics; D018360:Crystallography, X-Ray; D004268:DNA-Binding Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D004722:Endoribonucleases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D004926:Escherichia coli / Q000201:enzymology* / Q000235:genetics; D029968:Escherichia coli Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D008958:Models, Molecular; D017354:Point Mutation; D011487:Protein Conformation; D012329:RNA, Bacterial / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D013379:Substrate Specificity
chemical_list: D001426:Bacterial Proteins; C068356:CcdB protein, Plasmid F; D004268:DNA-Binding Proteins; D029968:Escherichia coli Proteins; C422954:MazE protein, E coli; C422955:MazF protein, E coli; D012329:RNA, Bacterial; D012333:RNA, Messenger; D004722:Endoribonucleases
keywords: crystal structure; persistence; ribonuclease; stress response; structure-function; substrate specificity; toxin-antitoxin