Yeast Ty retrotransposons assemble into virus-like particles whose T-numbers depend on the C-terminal length of the capsid protein.
The virus-like particles (VLPs) produced by the yeast Ty retrotransposons are structurally and functionally related to retroviral cores. Using cryo-electron microscopy (cryo-EM) and three-dimensional (3D) reconstruction, we have examined the structures of VLPs assembled from full-length and truncated forms of the capsid structural protein. The VLPs are highly polydisperse in their radius distribution. We have found that the length of the C-terminal region of the capsid structural protein dictates the T -number, and thus the size, of the assembled particles. Each construct studied appears to assemble into at least two or three size classes, with shorter C termini giving rise to smaller particles. This assembly property provides a model for understanding the variable assembly of retroviral core proteins. The particles are assembled from trimer-clustered units and there are holes in the capsid shells.
AL-Khayat
H A
HA
Birkbeck College, Malet Street, London, WC1E 7HX, UK.
Bhella
D
D
Kenney
J M
JM
Roth
J F
JF
Kingsman
A J
AJ
Martin-Rendon
E
E
Saibil
H R
HR
D002213:Capsid / Q000648:ultrastructure; D020285:Cryoelectron Microscopy; D005656:Fungal Proteins / Q000235:genetics; D007091:Image Processing, Computer-Assisted; D010316:Particle Size; D011487:Protein Conformation; D018626:Retroelements / Q000235:genetics*; D012441:Saccharomyces cerevisiae / Q000235:genetics*
D005656:Fungal Proteins; D018626:Retroelements