Shape shifter: redirection of prolate phage capsid assembly by staphylococcal pathogenicity islands.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 34737316.
- Also identified by DOI 10.1038/s41467-021-26759-x and PMC identifier 8569155.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
Staphylococcus aureus pathogenicity islands (SaPIs) are molecular parasites that hijack helper phages for their transfer. SaPIbov5, the prototypical member of a family of cos type SaPIs, redirects the assembly of ϕ12 helper capsids from prolate to isometric. This size and shape shift is dependent on the SaPIbov5-encoded protein Ccm, a homolog of the ϕ12 capsid protein (CP). Using cryo-electron microscopy, we have determined structures of prolate ϕ12 procapsids and isometric SaPIbov5 procapsids. ϕ12 procapsids have icosahedral end caps with T<sub>end</sub> = 4 architecture and a T<sub>mid</sub> = 14 cylindrical midsection, whereas SaPIbov5 procapsids have T = 4 icosahedral architecture. We built atomic models for CP and Ccm, and show that Ccm occupies the pentameric capsomers in the isometric SaPIbov5 procapsids, suggesting that preferential incorporation of Ccm pentamers prevents the cylindrical midsection from forming. Our results highlight that pirate elements have evolved diverse mechanisms to suppress phage multiplication, including the acquisition of phage capsid protein homologs.
Medical subject headings
- Staphylococcus