Dear all,
reconstructing and refining an icosahedral virus asymmetrically
with relion2 I get an extremely biased angular distribution that is
reflected in strong distortions (elongations). The bild file shows that
large parts of the sphere are completely empty (without any cylinders at
more or less opposite sides of the sphere) and some parts are highly
populated with the long red cylinders (at roughly 90° with respect to
the empty regions, see image attached). I have removed all particles
with the three angles being identical and used just one single copy but
the effect on the distortion is only very moderate. I am not sure
whether the particles are indeed oriented in this way (but would one not
expect that the preferred orientation would also have icosahedral
symmetry?) or whether this is rather a problem of the reconstruction
procedure. Does it make sense to thin out particles with similar angles
in the populated regions?
Can anybody please give me a hint how to proceed!
Thanks, Dieter
------------------------------------------------------------------------
Dieter Blaas,
Max F. Perutz Laboratories
Medical University of Vienna,
Inst. Med. Biochem., Vienna Biocenter (VBC),
Dr. Bohr Gasse 9/3,
A-1030 Vienna, Austria,
Tel: 0043 1 4277 61630,
Fax: 0043 1 4277 9616,
e-mail: [log in to unmask]
------------------------------------------------------------------------
|