toxN

Endoribonuclease ToxN

194 amino acids

Toxic component of a type III toxin-antitoxin (TA) system (PubMed:19124776). An endoribonuclease which cleaves between the first and second A of AAAAA sequences; it tolerates other nucleotides in positions +2 and +4 of the consensus. Digests cognate antitoxin RNA ToxI as shown by the 2'-3'-cyclic phosphate at the 3' end of the 34-nt repeats and probably other RNAs (PubMed:23267117). Inhibits growth when expressed in E.coli without causing cell lysis; this bacteriostatic effect is neutralized by cognate RNA antitoxin ToxI, which has 2.9 nearly identical 34 nucleotide-long repeats (PubMed:19124776). Non-cognate antitoxin RNA from P.atrosepticum does not inhibit this toxin (PubMed:23267117). The toxin-antitoxin pair function in plasmid maintenance (a plasmid addiction system), but unlike its P.atrosepticum homolog it is not seen to confer resistance to bacteriophages (PubMed:23267117).

Belongs to the ToxN/AbiQ toxin family.

22.887 kDa

MTNKDNPKFHTISTEYIDYLREADSKVPFNKDEQHSRPYVGVLEKINGHDYFVPLTSRNDKNFNSQVSVKLFDNDEKRIGVLLVNNMIPVPEKECKEIDIAEKTAADPQYGNLMLKQYLFLKENMDRVTNKVEKVYKDVTVQGKPSHKQKFLKGVCCDFPKLEEKCQEYKERDQAKERDKARRIAYMRQMGRER

toxN

Endoribonuclease ToxN

171 amino acids

The TA system protects P.atrosepticum strain 1043 against phage phiM1 and phiA2, E.coli against some but not all coliphages and S.marcescens against some bacteriophages, causing an abortive infection (Abi phenotype) (PubMed:19124776). Also protects P.atrosepticum strain 1043 against phage phiTE; phage that escape Abi and grow in this bacterium have evolved a pseudo-ToxI RNA by expanding a pre-existing sequence similar to the bona fide ToxI repeats (PubMed:23109916).

Belongs to the ToxN/AbiQ toxin family.

19.702 kDa

MKFYTISSKYIEYLKEFDDKVPNSEDPTYQNPKAFIGIVLEIQGHKYLAPLTSPKKWHNNVKESSLSCFKLHENGVPENQLGLINLKFMIPIIEAEVSLLDLGNMPNTPYKRMLYKQLQFIRANSDKIASKSDTLRNLVLQGKMQGTCNFSLLEEKYRDFGKEAEDTEEGE