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bottom segment of the bacteriophage M13 mini variantbottom segment of the bacteriophage M13 mini variant
Structural highlights
FunctionG3P_BPM13 Plays essential roles both in the penetration of the viral genome into the bacterial host via pilus retraction and in the extrusion process. During the initial step of infection, G3P mediates adsorption of the phage to its primary receptor, the tip of host F-pilus. Subsequent interaction with the host entry receptor tolA induces penetration of the viral DNA into the host cytoplasm. In the extrusion process, G3P mediates the release of the membrane-anchored virion from the cell via its C-terminal domain. Publication Abstract from PubMedFilamentous bacteriophages package their circular, single stranded DNA genome with the major coat protein pVIII and the minor coat proteins pIII, pVII, pVI, and pIX. Here, we report the cryo-EM structure of a ~500 A long bacteriophage M13 mini variant. The distal ends of the mini phage are sealed by two cap-like complexes composed of the minor coat proteins. The top cap complex consists of pVII and pIX, both exhibiting a single helix structure. Arg33 of pVII and Glu29 of pIX, located on the inner surface of the cap, play a key role in recognizing the genome packaging signal. The bottom cap complex is formed by the hook-like structures of pIII and pVI, arranged in helix barrels. Most of the inner ssDNA genome adopts a double helix structure with a similar pitch to that of the A-form double-stranded DNA. These findings provide insights into the assembly of filamentous bacteriophages. Cryo-EM structure of a bacteriophage M13 mini variant.,Jia Q, Xiang Y Nat Commun. 2023 Sep 5;14(1):5421. doi: 10.1038/s41467-023-41151-7. PMID:37669979[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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