[ccp4bb]: missing low resolution caused Fourier ripples?

[Jinghua Tang <jinghua@scripps.edu>]

***  For details on how to be removed from this list visit the  ***
***          CCP4 home page http://www.ccp4.ac.uk         ***


 Dear all,
   I am working on a virus structure. The experimental observation
contains data from 3.5 A to 50 A. From this data, I can see the virus
protein capsid quite clearly. But when I try to look for anything in the
RNA region in the center of the virus particle, I can only see some
concentric shells of electron density at 1/3 of the protein level. As I
understand that lack of enough low resolution infomation will generate
Fourier ripples in the electron density map also with concentric feature.
   I am very grateful for any suggestion on how to differentiate the
Fourier ripples effect and the real structure feature in the inside of the
virus.
   Is it reasonable to use low resolution reflection calculated from the
protein model to fill in the missing low resolution data to get rid of the
Fourier ripples effect? What CCP4 programs can be used to for this job?
   Thank you in advance for any suggestion!
   Jinghua