The Mottled Capsid of the Giant Phage SPN3US, a Likely Maturation Intermediate with a Novel Internal Shell
AuthorHeymann, J Bernard
Newcomb, William W
Winkler, Dennis C
Reilly, Erin R
Thomas, Julie A
Steven, Alasdair C
MetadataShow full item record
Abstract"Giant" phages have genomes of >200 kbp, confined in correspondingly large capsids whose assembly and maturation are still poorly understood. Nevertheless, the first assembly product is likely to be, as in other tailed phages, a procapsid that subsequently matures and packages the DNA. The associated transformations include the cleavage of many proteins by the phage-encoded protease, as well as the thinning and angularization of the capsid. We exploited an amber mutation in the viral protease gene of the Salmonella giant phage SPN3US, which leads to the accumulation of a population of capsids with distinctive properties. Cryo-electron micrographs reveal patterns of internal density different from those of the DNA-filled heads of virions, leading us to call them "mottled capsids". Reconstructions show an outer shell with T = 27 symmetry, an embellishment of the HK97 prototype composed of the major capsid protein, gp75, which is similar to some other giant viruses. The mottled capsid has a T = 1 inner icosahedral shell that is a complex network of loosely connected densities composed mainly of the ejection proteins gp53 and gp54. Segmentation of this inner shell indicated that a number of densities (~12 per asymmetric unit) adopt a "twisted hook" conformation. Large patches of a proteinaceous tetragonal lattice with a 67 Å repeat were also present in the cell lysate. The unexpected nature of these novel inner shell and lattice structures poses questions as to their functions in virion assembly.
cryoEM (cryo-electron microscopy)
single particle analysis
Identifier to cite or link to this itemhttp://hdl.handle.net/10713/13678
- To Be or Not To Be T4: Evidence of a Complex Evolutionary Pathway of Head Structure and Assembly in Giant <i>Salmonella</i> Virus SPN3US.
- Authors: Ali B, Desmond MI, Mallory SA, Benítez AD, Buckley LJ, Weintraub ST, Osier MV, Black LW, Thomas JA
- Issue date: 2017
- Global Proteomic Profiling of <i>Salmonella</i> Infection by a Giant Phage.
- Authors: Weintraub ST, Mohd Redzuan NH, Barton MK, Md Amin NA, Desmond MI, Adams LE, Ali B, Pardo S, Molleur D, Wu W, Newcomb WW, Osier MV, Black LW, Steven AC, Thomas JA
- Issue date: 2019 Mar 1
- Internal Proteins of the Procapsid and Mature Capsids of Herpes Simplex Virus 1 Mapped by Bubblegram Imaging.
- Authors: Wu W, Newcomb WW, Cheng N, Aksyuk A, Winkler DC, Steven AC
- Issue date: 2016 May 15
- Identification of Essential Genes in the Salmonella Phage SPN3US Reveals Novel Insights into Giant Phage Head Structure and Assembly.
- Authors: Thomas JA, Benítez Quintana AD, Bosch MA, Coll De Peña A, Aguilera E, Coulibaly A, Wu W, Osier MV, Hudson AO, Weintraub ST, Black LW
- Issue date: 2016 Nov 15
- Assembly of the herpes simplex virus capsid: characterization of intermediates observed during cell-free capsid formation.
- Authors: Newcomb WW, Homa FL, Thomsen DR, Booy FP, Trus BL, Steven AC, Spencer JV, Brown JC
- Issue date: 1996 Nov 1