Nhi

Contributors: Alba Herrero del Valle

Description

The Nhi (nuclease-helicase immunity) system targets and degrades specific phage DNA replication intermediates (N/A) . Nayeemul Bari et al. showed that Nhi from Staphylococcus epidermidis protects against a diverse panel of staphylococcal phages and Millman et al. showed that a protein Nhi-like (that shares the domain organization with Nhi but not the sequence) from Bacillus cereus protects against some Bacillus phages (N/A, N/A) .

Molecular mechanisms

Nhi contains two domains, a nuclease and a helicase domain that are both needed for the anti-phage activity. The nuclease domain has 3′–5′ exonuclease and plasmid nicking activities while the helicase unwinds dsDNA biderctionally. Nhi specifically recognizes phage single-stranded DNA binding proteins (SSB) that cover the phage genome to target this DNA for degradation thanks to its helicase and nuclease domains (N/A) .

Example of genomic structure

The Nhi is composed of 1 protein: Nhi.

Here is an example found in the RefSeq database:

The Nhi system in Staphylococcus sp. MZ9 (GCF_018622975.1, NZ_CP076029) is composed of 1 protein: Nhi (WP_045177897.1)

Distribution of the system among prokaryotes

Among the NaN complete genomes of RefSeq, the Nhi is detected in NaN genomes (NaN %). The system was detected in NaN different species.
phylum
Percent genome having the system
0
100
Minimum genomes count to display

Structure

Summary
Group
Structure
System
Gene name
Subtype
Proteins in structure
System genes
Prediction type
N genes in sys
pLDDT
iptm+ptm
pDockQ
No data available
Items per page:
10
0-0 of 0

Experimental validation

      
graph LR;
    Millman_2022[Millman et al., 2022] --> Origin_0
    Origin_0[ Nhi-like
Bacillus cereus] --> Expressed_0[Bacillus subtilis]
    Expressed_0[Bacillus subtilis] ----> phi3T & SpBeta & SPR
    Bari_2022[Bari et al., 2022] --> Origin_1
    Origin_1[Staphylococcus epidermidis 
AAW53361.1] --> Expressed_1[Staphylococcus epidermidis]
    Expressed_1[Staphylococcus epidermidis] ----> JBug18 & Pike & CNPx
    Bari_2022[Bari et al., 2022] --> Origin_1
    Origin_1[Staphylococcus epidermidis 
AAW53361.1] --> Expressed_2[Staphylococcus aureus]
    Expressed_2[Staphylococcus aureus] ----> Lorac
    Bari_2022[Bari et al., 2022] --> Origin_2
    Origin_2[Staphylococcus aureus 
WP_000632676.1] --> Expressed_3[Staphylococcus aureus]
    Expressed_3[Staphylococcus aureus] ----> Lorac
    Bari_2022[Bari et al., 2022] --> Origin_3
    Origin_3[Staphylococcus aureus 
WP_045177897.1] --> Expressed_4[Staphylococcus aureus]
    Expressed_4[Staphylococcus aureus] ----> Lorac
    Bari_2022[Bari et al., 2022] --> Origin_4
    Origin_4[Vibrio vulnificus 
WP_101958732.1] --> Expressed_5[Staphylococcus aureus]
    Expressed_5[Staphylococcus aureus] ----> Lorac
    subgraph Title1[Reference]
        Millman_2022
        Bari_2022
end
    subgraph Title2[System origin]
        Origin_0
        Origin_1
        Origin_1
        Origin_2
        Origin_3
        Origin_4
end
    subgraph Title3[Expression species]
        Expressed_0
        Expressed_1
        Expressed_2
        Expressed_3
        Expressed_4
        Expressed_5
end
    subgraph Title4[Protects against]
        phi3T
        SpBeta
        SPR
        JBug18
        Pike
        CNPx
        Lorac
        Lorac
        Lorac
        Lorac
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
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