Structural and functional analysis of the kid toxin protein from E. coli plasmid R1.
We have determined the structure of Kid toxin protein from E. coli plasmid R1 involved in stable plasmid inheritance by postsegregational killing of plasmid-less daughter cells. Kid forms a two-component system with its antagonist, Kis antitoxin. Our 1.4 A crystal structure of Kid reveals a 2-fold symmetric dimer that closely resembles the DNA gyrase-inhibitory toxin protein CcdB from E. coli F plasmid despite the lack of any notable sequence similarity. Analysis of nontoxic mutants of Kid suggests a target interaction interface associated with toxicity that is in marked contrast to that proposed for CcdB. A possible region for interaction of Kid with the antitoxin is proposed that overlaps with the target binding site and may explain the mode of antitoxin action.
Hargreaves
David
D
Krebs Institute for Biomolecular Research, Department of Molecular Biology and Biotechnology, University of Sheffield, Western Bank, United Kingdom.
Santos-Sierra
Sandra
S
Giraldo
Rafael
R
Sabariegos-Jareño
Rosario
R
de la Cueva-Méndez
Guillermo
G
Boelens
Rolf
R
Díaz-Orejas
Ramon
R
Rafferty
John B
JB
D000595:Amino Acid Sequence; D018360:Crystallography, X-Ray; D004926:Escherichia coli / Q000737:chemistry*; D029968:Escherichia coli Proteins / Q000737:chemistry* / Q000494:pharmacology*; D008958:Models, Molecular; D008969:Molecular Sequence Data; D010957:Plasmids; D011487:Protein Conformation; D017386:Sequence Homology, Amino Acid
D029968:Escherichia coli Proteins; C473072:kid toxin protein, E coli plasmid R1