Difference between revisions of "Part:BBa K1949030"

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yafO

Antitoxin YafN inhibit function of toxin YafO

Toxin-Antitoxin (TA) systems consist of stable toxin protein which attacks essential factors needed for cell growth, and unstable antitoxin protein which negates the function of toxin. In E. coli genome, there are many operons coding gene of these proteins. Among them, toxin proteins which work as RNA interferase cleaving unspecified mRNA are particularly known. When they function, inhibition of cell growth or cell killing can be induced. YafO is one of these toxins and YafN is co-expressed cognate antitoxin.

YafO is mRNA interferase, that is, it cleaves mRNA by endonuclease activity and inhibits protein synthesis. It is thought that YafO endonuclease activity is induced by binding to 50S subunit in 70S ribosome. Yafo is a rebosome-dependent mRNA interferase and cleaves coding regions of mRNAs.

It is also considered that YafO inhibits translation in two steps. Initially, the binding of the toxin to 70S ribosomes inhibits translation reversibly via binding with its cognate antitoxin. However, in the second step, as the toxin binding to ribosomes is prolonged, the latent ribonuclease activity of the toxin is induced to cleave mRNAs, which results in irreversible inhibition of protein synthesis.

Characterization

Sequence and Features