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Publication Abstract from PubMed

AbiQ is a phage resistance mechanism found on a native plasmid of Lactococcus lactis that abort virulent phage infections. In this study, we experimentally demonstrate that AbiQ belongs to the recently described type III toxin-antitoxin systems. When overexpressed, the AbiQ protein (ABIQ) is toxic and causes bacterial death in a bacteriostatic manner. Northern and Western blot experiments revealed that the abiQ gene is transcribed and translated constitutively, and its expression is not activated by a phage product. ABIQ is an endoribonuclease that specifically cleaves its cognate antitoxin RNA molecule in vivo. The crystal structure of ABIQ was solved and site-directed mutagenesis identified key amino acids for its anti-phage and/or its RNase function. The AbiQ system is the first lactococcal abortive infection system characterized to date at a structural level.

Structure and activity of AbiQ, a lactococcal endoribonuclease belonging to the type III toxin-antitoxin system.,Samson JE, Spinelli S, Cambillau C, Moineau S Mol Microbiol. 2012 Dec 20. doi: 10.1111/mmi.12129. PMID:23279123^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.