Zorya

Contributors: Florian Tesson

Description

The Zorya defense system was discovered in 2018 () among other systems.

All subtypes of Zorya are composed of at least two proteins named ZorA and ZorB. In certain subtypes, additional proteins can be involved in the system (ZorC and ZorD in type I Zorya, ZorE in type II, or ZorF and ZorG type III).

Molecular mechanism

The molecular mechanism of type I Zoya was recently described () . ZorA and ZorB were shown to form a transmembrane heteromer with 5:2 (ZorA:ZorB) stoechiometry. The protein complex acts as a peptidoglycan-binding rotary motor. The structure shows that the 5 ZorA proteins form a long tail inside the cytoplasm. Part of this tail has amino acid homology with the core signaling unit of the bacterial chemosensory array suggesting that the ZorA tail is responsible for the activation of ZorC and ZorD () .

On the other hand, ZorC and ZorD interact with DNA () and ZorD acts as an ATP-dependent nuclease.

With all those results, the mechanism suggested by the authors is () :

  • Detection of the phage infection by the ZorAB complex (sensing either cell wall depression or inner membrane curvature)
  • Signal transduction from ZorA tail to ZorC and ZorD
  • DNA binding by ZorC/D and DNA cleavage by ZorD close to the injection site.

Example of genomic structure

A total of 2 subsystems have been described for the Zorya system.

Here is some examples found in the RefSeq database:

The Zorya_TypeI system in Erwinia pyrifoliae (GCF_000027265.1, NC_012214) is composed of 4 proteins ZorA (WP_012666948.1) ZorB (WP_012666949.1) ZorC (WP_012666950.1) ZorD (WP_012666951.1)

The Zorya_TypeII system in Pectobacterium aroidearum (GCF_015689195.1, NZ_CP065044) is composed of 3 proteins ZorA2 (WP_205947278.1) ZorB (WP_205947279.1) ZorE (WP_205947280.1)

Distribution of the system among prokaryotes

Among the 22,803 complete genomes of RefSeq, the Zorya is detected in 803 genomes (3.52 %).

The system was detected in 310 different species.

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

Structure

Zorya_TypeI

Example 1

Zorya_TypeII

Example 1

Experimental validation

      
graph LR;
    Doron_2018[Doron et al., 2018] --> Origin_0
    Origin_0[ Type I
Escherichia coli 
ABV17222.1, ABV17786.1,
ABV16709.1, ABV17208.1] --> Expressed_0[Escherichia coli]
    Expressed_0[Escherichia coli] ----> LambdaVir & SECphi27 & T7
    Doron_2018[Doron et al., 2018] --> Origin_1
    Origin_1[ Type II
Escherichia coli 
ACA79490.1, ACA79491.1,
ACA79492.1] --> Expressed_1[Escherichia coli]
    Expressed_1[Escherichia coli] ----> T7 & SECphi17
    Payne_2021[Payne et al., 2021] --> Origin_2
    Origin_2[ Type III
Stenotrophomonas nitritireducens 
WP_055768786.1, WP_055768783.1,
WP_055768781.1, WP_055768778.1] --> Expressed_2[Escherichia coli]
    Expressed_2[Escherichia coli] ----> T1 & T4 & T7 & LambdaVir & PVP-SE1
    subgraph Title1[Reference]
        Doron_2018
        Payne_2021
end
    subgraph Title2[System origin]
        Origin_0
        Origin_1
        Origin_2
end
    subgraph Title3[Expression species]
        Expressed_0
        Expressed_1
        Expressed_2
end
    subgraph Title4[Protects against]
        LambdaVir
        SECphi27
        T7
        T7
        SECphi17
        T1
        T4
        T7
        LambdaVir
        PVP-SE1
end
    style Title1 fill:none,stroke:none,stroke-width:none
    style Title2 fill:none,stroke:none,stroke-width:none
    style Title3 fill:none,stroke:none,stroke-width:none
    style Title4 fill:none,stroke:none,stroke-width:none

    

References

10.1093/nar/gkab883
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10.1126/science.aar4120
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10.1101/2023.12.18.572097
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10.1016/j.sbi.2023.102565
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