Update zorya.md

Add description and mechanism #260 (closed)

content/3.defense-systems/zorya.md

@@ -10,12 +10,34 @@ tableColumns:
     Activator: Unknown
     Effector: Unknown
     PFAM: PF00176, PF00271, PF00691, PF04851, PF15611
+contributors:
+    - Florian Tesson
 relevantAbstracts:
     - doi: 10.1093/nar/gkab883
     - doi: 10.1126/science.aar4120
+    - doi: 10.1101/2023.12.18.572097
 ---
 
 # Zorya
+
+## Description
+
+The Zorya defense system was discovered in 2018 :ref{doi=10.1126/science.aar4120} 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 :ref{doi=10.1101/2023.12.18.572097}. 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 :ref{doi=10.1016/j.sbi.2023.102565}.
+
+On the other hand, ZorC and ZorD interact with DNA :ref{doi=10.1101/2023.12.18.572097} and ZorD acts as an ATP-dependent nuclease.
+
+With all those results, the mechanism suggested by the authors is :ref{doi=10.1101/2023.12.18.572097}:
+- 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.
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 </mermaid>
 
+