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Cryo-electron microscopy structure of the filamentous bacteriophage IKe
The filamentous bacteriophage IKe infects Escherichia coli cells bearing IncN pili. We report the cryo-electron microscopy structure of the micrometer-long IKe viral particle at a resolution of 3.4 Å. The major coat protein [protein 8 (p8)] consists of 47 residues that fold into a ∼68-Å-long helix....
Autores principales: | , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
National Academy of Sciences
2019
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6431161/ https://www.ncbi.nlm.nih.gov/pubmed/30819888 http://dx.doi.org/10.1073/pnas.1811929116 |
Sumario: | The filamentous bacteriophage IKe infects Escherichia coli cells bearing IncN pili. We report the cryo-electron microscopy structure of the micrometer-long IKe viral particle at a resolution of 3.4 Å. The major coat protein [protein 8 (p8)] consists of 47 residues that fold into a ∼68-Å-long helix. An atomic model of the coat protein was built. Five p8 helices in a horizontal layer form a pentamer, and symmetrically neighboring p8 layers form a right-handed helical cylinder having a rise per pentamer of 16.77 Å and a twist of 38.52°. The inner surface of the capsid cylinder is positively charged and has direct interactions with the encapsulated circular single-stranded DNA genome, which has an electron density consistent with an unusual left-handed helix structure. Similar to capsid structures of other filamentous viruses, strong capsid packing in the IKe particle is maintained by hydrophobic residues. Despite having a different length and large sequence differences from other filamentous phages, π–π interactions were found between Tyr9 of one p8 and Trp29 of a neighboring p8 in IKe that are similar to interactions observed in phage M13, suggesting that, despite sequence divergence, overall structural features are maintained. |
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