S. Kronenberg et al., Electron cryo-microscopy and image reconstruction of adeno-associated virus type 2 empty capsids, EMBO REP, 2(11), 2001, pp. 997-1002
Adeno-associated virus type 2 empty capsids are composed of three proteins,
VP1, VP2 and VP3, which have relative molecular masses of 87, 72 and 62 kD
a, respectively, and differ in their N-terminal amino acid sequences. They
have a likely molar ratio of 1:1:8 and occupy symmetrical equivalent positi
ons in an icosahedrally arranged protein shell. We have investigated empty
capsids of adeno-associated virus type 2 by electron cryo-microscopy and ic
osahedral image reconstruction. The three-dimensional map at 1.05 nm resolu
tion showed sets of three elongated spikes surrounding the three-fold symme
try axes and narrow empty channels at the five-fold axes. The inside of the
capsid superimposed with the previously determined structure of the canine
parvovirus (Q. Me and M.S. Chapman, 1996, J. Mol. BioL, 264, 497-520), whe
reas the outer surface showed clear discrepancies. Globular structures at t
he inner surface of the capsid at the two-fold symmetry axes were identifie
d as possible positions for the N-terminal extensions of VP1 and VP2.