Download MendeleyCryo-EM structure of cyanopodophage A4 reveals a pentameric pre-ejectosome in the double-stabilized capsid.
Hou, P., Zhou, R.Q., Jiang, Y.L., Yu, R.C., Du, K., Gan, N., Ke, F., Zhang, Q.Y., Li, Q., Zhou, C.Z.(2025) Proc Natl Acad Sci U S A 122: e2423403122-e2423403122
- PubMed: 40163721
- DOI: https://doi.org/10.1073/pnas.2423403122
- Primary Citation of Related Structures:
9JWB, 9K09, 9K2V, 9K3A - 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, 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 Anabaena 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.
Organizational Affiliation:
Department of Radiology, The First Affiliated Hospital of University of Science and Technology of China and School of Life Sciences, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei 230027, China.
