The structure of a Ty3 retrotransposon capsid C-terminal domain dimer

Structure of the Ty3/Gypsy retrotransposon capsid and the evolution of retroviruses.

The Ty3 particles have a T=9 and each asymmetric unit of the lattice contains nine non-symmetry related Ty3 capsid protein monomers. We extracted all non-symmetry related units from the final reconstructions from the two half datasets. The CA-CTDs were aligned and averaged separately. The final structure of the CA-CTD comes from nine averaged copies of the domain. The final structure of the CA-CTD was resolved at 4.9 A resolution at 0.143 FSC. Gaussian-smoothened ellipsoid-shaped masks were used for resolution measurements.

The 9 non-symmetry related copies of the Ty3 Capsid-CTD from the complete capsid shell structure were aligned and averaged to generate a higher resolution 4.9 A structure

Cryo-grids containing purified PR- Ty3 particles were imaged in a Titan Krios electron microscope equipped with a Falcon II direct electron detector, operated at 300 kV. Images were collected with a nominal magnification of 75000, giving a pixel size of 1.08 A. Images were collected in integrating mode with a total electron dose of 20 e/A2. The range of applied defocus values was between -1.0 um and -3.5 um.

The sample was applied onto glow-discharged C-flat (Protochips Inc.) holey carbon grids. The grids were blotted from the back side for 11 seconds at room temperature in a chamber at 85% humidity and plunge-frozen into liquid ethane using a manual plunger.

1733 vesicles and near-complete buds were picked from 61 tomograms. Subtomograms were extracted from the surface of the vesicles.

D336I mutation in the active center of the Ty3 protease

Gag3-Pol3,Transposon Ty3-2 TYA-TYB polyprotein

MSFMDQIPGGGNYPKLPVECLPNFPIQPSLTFRGRNDSHKLKNFISEIMLNMSMISWPNDASRIVYCRRHLLNPAAQWAN
DFVQEQGILEITFDTFIQGLYQHFYKPPDINKIFNAITQLSEAKLGIERLNQRFRKIWDRMPPDFMTEKAAIMTYTRLLT
KETYNIVRMHKPETLKDAMEEAYQTTALTERFFPGFELDADGDTIIGATTHLQEEYDSDYDSEDNLTQNRYVHTVRTRRS
YNKPMSNHRNRRNNNASREECIKNRLCFYCKKEGHRLNECRARKAVLTDLELESKDQQTLFIKTLPIVH

Saccharomyces cerevisiae (strain ATCC 204508 / S288c)
strain yVB1680 strain - BY4741 killer minus, Ty3 null

Medical Research Council (United Kingdom)

Ty3, retrotransposon, retrovirus, capsid, Gag polyprotein, capsid-CTD, VIRUS LIKE PARTICLE