Competing scaffolding proteins determine capsid size during mobilization of Staphylococcus aureus pathogenicity islands

Abstract
Data availability
Article and author information
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Abstract

Staphylococcus aureus pathogenicity islands (SaPIs), such as SaPI1, exploit specific helper bacteriophages, like 80a, for their high frequency mobilization, a process termed 'molecular piracy'. SaPI1 redirects the helper's assembly pathway to form small capsids that can only accommodate the smaller SaPI1 genome, but not a complete phage genome. SaPI1 encodes two proteins, CpmA and CpmB, that are responsible for this size redirection. We have determined the structures of the 80a and SaPI1 procapsids to near-atomic resolution by cryo-electron microscopy, and show that CpmB competes with the 80a scaffolding protein (SP) for a binding site on the capsid protein (CP), and works by altering the angle between capsomers. We probed these interactions genetically and identified second-site suppressors of lethal mutations in SP. Our structures show, for the first time, the detailed interactions between SP and CP in a bacteriophage, providing unique insights into macromolecular assembly processes.

Data availability

The following data sets were generated

1. Kizziah
2. J.L.
3. Dearborn
4. A.D.
5. Dokland
6. T.
(2017) Capsid protein and C-terminal part of scaffolding protein in the Staphylococcus aureus phage 80alpha procapsid
Publicly available at the EMBL-EBI EM Data Bank with accession number -EMDB-7030.

https://www.ebi.ac.uk/pdbe/entry/emdb/EMD-7030
1. Kizziah
2. J.L.
3. Dearborn
4. A.D.
5. Dokland
6. T.
(2017) Capsid protein and C-terminal part of scaffolding protein in the Staphylococcus aureus phage 80alpha procapsid
Publicly available at the RCSB Protein Data Bank with accession number 6B0X.

https://www.rcsb.org/pdb/explore/explore.do?structureId=6B0X
1. Kizziah
2. J.L.
3. Dearborn
4. A.D.
5. Dokland
6. T.
(2017) Capsid protein and C-terminal part of CpmB protein in the Staphylococcus aureus pathogenicity island 1 80alpha-derived procapsid
Publicly available at the EMBL-EBI EM Data Bank with accession number -EMDB-7035.

https://www.ebi.ac.uk/pdbe/entry/emdb/EMD-7035
1. Kizziah
2. J.L.
3. Dearborn
4. A.D.
5. Dokland
6. T.
(2017) Capsid protein and C-terminal part of CpmB protein in the Staphylococcus aureus pathogenicity island 1 80alpha-derived procapsid
Publicly available at the RCSB Protein Data Bank with accession number 6B23.

https://www.rcsb.org/pdb/explore/explore.do?structureId=6B23

Article and author information

Author details

Altaira D Dearborn

Protein Expression Laboratory, National Institute of Arthritis and Musculoskeletal and Skin Diseases, National Institutes of Health, Bethesda, United States

Competing interests
The authors declare that no competing interests exist.
Erin A Wall

Department of Microbiology and Immunology, Virginia Commonwealth University, Richmond, United States

Competing interests
The authors declare that no competing interests exist.
James L Kizziah

Department of Microbiology, University of Alabama at Birmingham, Birmingham, United States

Competing interests
The authors declare that no competing interests exist.
Laura Klenow

Department of Microbiology and Immunology, Virginia Commonwealth University, Richmond, United States

Competing interests
The authors declare that no competing interests exist.
Laura K Parker

Department of Microbiology and Immunology, Virginia Commonwealth University, Richmond, United States

Competing interests
The authors declare that no competing interests exist.
Keith A Manning

Department of Microbiology, University of Alabama at Birmingham, Birmingham, United States

Competing interests
The authors declare that no competing interests exist.
Michael S Spilman

Direct Electron, LP, San Diego, United States

Competing interests
The authors declare that no competing interests exist.
John M Spear

Biological Science Imaging Resource, Florida State University, Tallahassee, United States

Competing interests
The authors declare that no competing interests exist.
Gail E Christie

Department of Microbiology and Immunology, Virginia Commonwealth University, Richmond, United States

Competing interests
The authors declare that no competing interests exist.
Terje Dokland

Department of Microbiology, University of Alabama at Birmingham, Birmingham, United States

For correspondence
dokland@uab.edu

Competing interests
The authors declare that no competing interests exist.

"This ORCID iD identifies the author of this article:" 0000-0001-5655-4123

Funding

National Institutes of Health (R01 AI083255)

Terje Dokland

The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.

Copyright

This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.