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Title | Cryo-EM structure of cyanopodophage A4 reveals a pentameric pre-ejectosome in the double-stabilized capsid. |
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Journal, issue, pages | Proc Natl Acad Sci U S A, Vol. 122, Issue 14, Page e2423403122, Year 2025 |
Publish date | Apr 8, 2025 |
![]() | Pu Hou / Rui-Qian Zhou / Yong-Liang Jiang / Rong-Cheng Yu / Kang Du / Nanqin Gan / Fei Ke / Qi-Ya Zhang / Qiong Li / Cong-Zhao Zhou / ![]() |
PubMed Abstract | Upon infection, the podophages usually eject a couple of proteins from the capsid to form a transmembrane ejectosome on the host cell membrane that facilitates the ejection of viral genome. However, ...Upon infection, the podophages usually eject a couple of proteins from the capsid to form a transmembrane ejectosome on the host cell membrane that facilitates the ejection of viral genome. However, it remains unclear how these proteins of pre-ejectosome are finely assembled at the center of highly packaged genome. Here, we report the intact structure of cyanopodophage A4, which consists of a capsid stabilized by two types of cement proteins and a short tail attached with six tail fibers. Notably, we find a pentameric pre-ejectosome at the core of capsid, which is composed of four ejection proteins wrapped into a coaxial cylinder of triple layers. Moreover, a segment of genomic DNA runs along the positively charged circular cleft formed by two ejection proteins. Based on the mortise-and-tenon architecture of pre-ejectosome in combination with previous studies, we propose a putative DNA packaging process and ejection mechanism for podophages. These findings largely enrich our knowledge on the assembly mechanism of podophages, which might facilitate the application of A4 as a chassis cyanophage in synthetic biology. |
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Methods | EM (single particle) |
Resolution | 2.6 - 3.6 Å |
Structure data | EMDB-61850, PDB-9jwb: EMDB-61942, PDB-9k09: EMDB-61998, PDB-9k2v: EMDB-62011, PDB-9k3a: |
Chemicals | ![]() ChemComp-ZN: |
Source |
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![]() | VIRUS / Cyanophage / Capsid / VIRAL PROTEIN / Tail / Portal / Zozzle / Adaptor / Tail Fiber / Ejectosome |