Structural highlights
Function
[PEMK_ECOLX] Toxic component of a type II toxin-antitoxin (TA) module. Probably functions as an endoribonuclease. Responsible for the stable maintenance of the plasmid during cell division by postsegregational killing of plasmid-less daughter cells. Neutralized by coexpression with cognate antitoxin PemI. Both PemI and PemK proteins bind to the promoter region of the pem operon to autoregulate their synthesis.[1] [2]
Evolutionary Conservation
Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf.
Publication Abstract from PubMed
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.
Structural and functional analysis of the kid toxin protein from E. coli plasmid R1.,Hargreaves D, Santos-Sierra S, Giraldo R, Sabariegos-Jareno R, de la Cueva-Mendez G, Boelens R, Diaz-Orejas R, Rafferty JB Structure. 2002 Oct;10(10):1425-33. PMID:12377128[3]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
References
- ↑ Tsuchimoto S, Ohtsubo H, Ohtsubo E. Two genes, pemK and pemI, responsible for stable maintenance of resistance plasmid R100. J Bacteriol. 1988 Apr;170(4):1461-6. PMID:2832364
- ↑ Tsuchimoto S, Ohtsubo E. Autoregulation by cooperative binding of the PemI and PemK proteins to the promoter region of the pem operon. Mol Gen Genet. 1993 Feb;237(1-2):81-8. PMID:8455570
- ↑ Hargreaves D, Santos-Sierra S, Giraldo R, Sabariegos-Jareno R, de la Cueva-Mendez G, Boelens R, Diaz-Orejas R, Rafferty JB. Structural and functional analysis of the kid toxin protein from E. coli plasmid R1. Structure. 2002 Oct;10(10):1425-33. PMID:12377128
