[ccp4bb] How to generate cif file?

[Gaelle PESCE]

Dear all,

In my protein structure I found a modified Tyrosine that is covalently 
bound to a nucleotide by a phosphodiester bound.

I am having problem to generate the library description for such a 
modification. Would someone have any ideas on how to generate such a cif 
file?

Thanks in advance.

Regards,

Gaelle