title: AbiQ
layout: article
tableColumns:
article:
doi: 10.1016/j.mib.2005.06.006
abstract: |
Abortive infection (Abi) systems, also called phage exclusion, block phage multiplication and cause premature bacterial cell death upon phage infection. This decreases the number of progeny particles and limits their spread to other cells allowing the bacterial population to survive. Twenty Abi systems have been isolated in Lactococcus lactis, a bacterium used in cheese-making fermentation processes, where phage attacks are of economical importance. Recent insights in their expression and mode of action indicate that, behind diverse phenotypic and molecular effects, lactococcal Abis share common traits with the well-studied Escherichia coli systems Lit and Prr. Abis are widespread in bacteria, and recent analysis indicates that Abis might have additional roles other than conferring phage resistance.
Sensor: Unknown
Activator: Unknown
Effector: Unknown
PFAM: PF13958
contributors:
- Florian Tesson
relevantAbstracts:
- doi: 10.1023/A:1002027321171
- doi: 10.1016/j.mib.2005.06.006
- doi: 10.1128/AEM.64.12.4748-4756.1998
- doi: 10.1111/mmi.12129AbiQ
Description
AbiQ was discovered in 1998 on Lactococcus lactis plasmid :ref{doi=10.1128/AEM.64.12.4748-4756.1998}.
AbiQ is one of the so-called "Abi" systems for "Abortive infection" discovered in the 90's in research related to the dairy industry :ref{doi=10.1016/j.mib.2005.06.006}. AbiQ is classified as abortive infection in :ref{doi=10.1016/j.mib.2023.102312}.
AbiQ is composed of a single protein AbiQ and an RNA antitoxin (antiQ) :ref{doi=10.1111/mmi.12129}.
Molecular mechanism
AbiQ act as an anti-toxin type III. AbiQ is an RNAase that will bind its antitoxin antiQ :ref{doi=10.1111/mmi.12129}.
The AbiQ is constitutively expressed and bind to its antiQ RNA resulting in an inactivated AbiQ. To get activated, AbiQ needs the concentration of antiQ to decrease. However, during phage infection, the expression of the antiQ is constant and the authors do not know how the AbiQ is activated :ref{doi=10.1111/mmi.12129}.
Example of genomic structure
The AbiQ is composed of 1 protein: AbiQ.
Here is an example found in the RefSeq database:
The AbiQ system in Planococcus faecalis (GCF_002009235.1, NZ_CP019401) is composed of 1 protein: AbiQ (WP_078080483.1)
Distribution of the system among prokaryotes
Among the 22,803 complete genomes of RefSeq, the AbiQ is detected in 258 genomes (1.13 %).
The system was detected in 111 different species.
Proportion of genome encoding the AbiQ system for the 14 phyla with more than 50 genomes in the RefSeq database.
Structure
Experimentally determined structure
From :ref{doi=10.1111/mmi.12129} in Lactococcus lactis:
::molstar-pdbe-plugin
height: 700 dataUrl: /abiq/4glk_LlAbiQ_1mer.cif
::
Structure
AbiQ
Example 1
::molstar-pdbe-plugin
height: 700 dataUrls:
- /abiq/AbiQ__AbiQ.cif
::