abie.md

title: AbiE
tableColumns:
    doi: 10.1016/j.mib.2005.06.006

AbiE is a family of an anti-phage defense systems. They act through a Toxin-Antitoxin mechanism, and are comprised of a pair of genes, with one gene being toxic while the other confers immunity to this toxicity. 

It is classified as an Abortive infection system.

Molecular mechanism

AbiE systems are encoded by two mandatory genes, abiEi and abiEii (1,2).  The latter encodes for AbiEii, a GTP-binding nucleotidyltransferase (NTase) which expression induce a reversible growth arrest.  On the other hand, abiEi encodes for a AbiEi a transcriptional autorepressor that  binds to the promoter of the abiE operon.

Based on this mechanisms, AbiE systems are classified as Type IV Toxin-Antitoxin system, where the antitoxin and toxin are both proteins that do not directly interact with each other.

Example of genomic structure

The AbiE system is composed of 2 proteins: AbiEi_1 and, AbiEii.

Here is an example found in the RefSeq database:

AbiE system in the genome of Desulfuromonas versatilis (GCF_019704135.1) is composed of 2 proteins: AbiEi_1 (WP_221251730.1)and, AbiEii (WP_221251731.1).

Distribution of the system among prokaryotes

The AbiE system is present in a total of 962 different species.

Among the 22k complete genomes of RefSeq, this system is present in 3742 genomes (16.4 %).

Proportion of genome encoding the AbiE system for the 14 phyla with more than 50 genomes in the RefSeq database.

Experimental validation

AbiE systems were experimentally validated using:

A system from lactococcal plasmid in lactococci has an anti-phage effect against 936 (Chopin et al., 2005)

Relevant abstracts

::article-doi-list

items: - 10.1023/A:1002027321171 - 10.1016/j.mib.2005.06.006 - 10.1093/nar/gkt1419

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