Zeta toxin protein domain

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PDB 1ly1 EBI.jpg
structure and mechanism of t4 polynucleotide kinase
Symbol Zeta_toxin
Pfam PF06414
Pfam clan CL0023
InterPro IPR010488
SCOP 1gvn

In molecular biology, the protein domain Zeta (ζ) toxin refers to a protein domain found in prokaryotes, which acts as a UDP-N-acetylglucosamine kinase.[1] Its function is to inhibit cell wall biosynthesis and it may act as a bactericide in nature. It is also thought that Zeta toxin induces reversible protective dormancy and permeation to propidium iodide (PI).[2]


This protein family entry consists of several bacterial zeta toxin proteins. Zeta toxin is thought to be part of a postsegregational killing (PSK) system involved in the killing of plasmid-free cells. It relies on antitoxin/toxin systems that secure stable inheritance of low and medium copy number plasmids during cell division and kill cells that have lost the plasmid.[3]


The Zeta Toxin is folded like a phosphotransferase. This domain features an α/β structure and the central twisted β-sheet contains six β-strands. The first 5 strands are parallel but β-strand 6 is antiparallel and connected by a short loop to β-strand 5. α-Helices are inserted between and flank the β-strands.[3]


  1. ^ Mutschler, H., Gebhardt, M., Shoeman, R.L. and Meinhart, A. (2011). "A novel mechanism of programmed cell death in bacteria by toxin-antitoxin systems corrupts peptidoglycan synthesis". PLoS Biol. 9: #e1001033–e1001033. doi:10.1371/journal.pbio.1001033. PMC 3062530Freely accessible. PMID 21445328. 
  2. ^ Lioy VS, Machon C, Tabone M, Gonzalez-Pastor JE, Daugelavicius R, Ayora S, et al. (2012). "The ζ toxin induces a set of protective responses and dormancy". PLoS ONE. 7 (1): e30282. doi:10.1371/journal.pone.0030282. PMC 3266247Freely accessible. PMID 22295078. 
  3. ^ a b Meinhart A, Alonso JC, Sträter N, Saenger W (February 2003). "Crystal structure of the plasmid maintenance system epsilon/zeta: functional mechanism of toxin zeta and inactivation by epsilon 2 zeta 2 complex formation". Proc. Natl. Acad. Sci. U.S.A. 100 (4): 1661–6. doi:10.1073/pnas.0434325100. PMC 149889Freely accessible. PMID 12571357. 

This article incorporates text from the public domain Pfam and InterPro IPR010488