---
title: AbiE
tableDescription: 
  doi: 10.1093/nar/gkt1419
  other: blabla
---

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](/abie/AbiE.svg){max-width=750px}

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 %).

![abie](/abie/Distribution_AbiE.svg){max-width=750px}

*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

---
::