Icosahedral T=3 symmetry in cryosparc

3D Refinement
1

Dear all,

I am curious to pick out Flock House virus particles from my micrographs. Based on published information, FHV capside is under T=3 Icosahedral symmetry. In refinement step, what parameter of symmetry should I use? I tried T3 and I3, both gave me an error but only I1 worked, it seems a correct output, but does I1 mean just Icosahedral ?

Super thanks!
Hong

3

Hi Hong,

The number that you specified (T=3) is just the T number defined by the h and k values of an icosahedral virus. This link explains the T-numbers well (Icosahedric capsids, Caspar and Klug ~ ViralZone). This means there is no T3 or I3 point group to apply as I in itself is a group of symmetries and doesn’t need a numeric qualifier. “I” should be good enough for the refinements to work.

Vamsee

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4

Thank you Vamsee for the explanation and the useful link! Yes, I is enough for a good refinement!.

Hong