hna.md

title: Hna
layout: article
tableColumns:
    article:
      doi: 10.1016/j.chom.2023.01.010
      abstract: |
        There is strong selection for the evolution of systems that protect bacterial populations from viral attack. We report a single phage defense protein, Hna, that provides protection against diverse phages in Sinorhizobium meliloti, a nitrogen-fixing alpha-proteobacterium. Homologs of Hna are distributed widely across bacterial lineages, and a homologous protein from Escherichia coli also confers phage defense. Hna contains superfamily II helicase motifs at its N terminus and a nuclease motif at its C terminus, with mutagenesis of these motifs inactivating viral defense. Hna variably impacts phage DNA replication but consistently triggers an abortive infection response in which infected cells carrying the system die but do not release phage progeny. A similar host cell response is triggered in cells containing Hna upon expression of a phage-encoded single-stranded DNA binding protein (SSB), independent of phage infection. Thus, we conclude that Hna limits phage spread by initiating abortive infection in response to a phage protein.
    PFAM: PF00270, PF04851, PF13307

Hna

To do

Example of genomic structure

The Hna is composed of 1 protein: Hna.

Here is an example found in the RefSeq database:

The Hna system in Aggregatimonas sangjinii (GCF_005943945.1, NZ_CP040710) is composed of 1 protein: Hna (WP_138852947.1)

Distribution of the system among prokaryotes

Among the 22,803 complete genomes of RefSeq, the Hna is detected in 493 genomes (2.16 %).

The system was detected in 305 different species.

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

Structure

Hna

::molstar-pdbe-plugin

height: 700 dataUrl: /hna/Hna__Hna-plddts_91.2064.pdb

::

Experimental validation

graph LR; Doron_2018[Doron et al., 2018] --> Origin_0 Origin_0[Sinorhizobium meliloti AAK65868.1] --> Expressed_0[Sinorhizobium meliloti] Expressed_0[Sinorhizobium meliloti] ----> 5A & 3K Sather_2023[Sather et al., 2023] --> Origin_1 Origin_1[Escherichia coli RDP84117.1] --> Expressed_1[Escherichia coli] Expressed_1[Escherichia coli] ----> T3 & T4 & T7 & HK97 subgraph Title1[Reference] Doron_2018 Sather_2023 end subgraph Title2[System origin] Origin_0 Origin_1 end subgraph Title3[Expression species] Expressed_0 Expressed_1 end subgraph Title4[Phage infected] 5A 3K T3 T4 T7 HK97 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 ## Relevant abstract ::relevant-abstracts --- items: - doi: 10.1016/j.chom.2023.01.010

---

::