[ccp4bb]: Side Chain Assignement

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Dear CCP4 users,

I am refining a structure at 1.9 A resolution, spacegroup P212121, one molecule
per assymetric unit. Unfortunatelly the primary structure for this protein is
unkonw (purified protein), but its tertiary structure was solved (main chain and
pseudo-side chains). This "pseudo-model" is refined and the R-factor and R-free
are around 19%. Initial MIRAS phases are reliable and initial map is practically
continuous in all its extension. My question is: Is there any program that uses
this pseudo-model and the initial MIRAS map (or an omit-map) to validate the
side chain and/or to guess the most probably side-chain? I am not sure if at 1.9
A I will be able to distinguish between Leu, Asn and Asp (as an example) solely
by the electron density... Cysteine, Methione residues can be identified by the
anomalous signal and the peak in the 2Fo-Fc map. Other residues are easily
identified (Proline, Arginine, Tyrosine ...) but what can I do distinguish
between Leu/Asn/Asp, Gln/Glu, Val/Thr...?
Amino acid sequence analysis is under way, but it may take a while since this is
a big protein.

Any help is welcome!

All the best

Ronaldo Nagem.