CRYOELECTRON MICROSCOPY STRUCTURE OF YEAST TY RETROTRANSPOSON VIRUS-LIKE PARTICLES

The virus like particles (VLPs) produced by the yeast retrotransposon Ty1 are functionally related to retroviral cores. These particles are unusual in that they have variable radii. A paired mass-radius analysi s of VLPs by scanning transmission electron microscopy showed that man y of these particles farm an icosahedral T-number series. Three-dimens ional reconstruction to 38-Angstrom resolution from cryo-electron micr ographs of T=3 and T=4 shells revealed that the single structural prot ein encoded by the TYA gene assembles into spiky shells from trimeric units.