[ccp4bb]: Re: Chain identifiers in PROTIN/REFMAC

["Eleanor J. Dodson" <ccp4@ysbl.york.ac.uk>]

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Sugoto wrote:
> 
> Dear all
> 
> I am not aware whether this might have been discussed earlier. I have
> a three-chain trimer as the asymmetric unit and sixty such asymmetric
> units form the complete molecule - typical arrangement in a T=3 virus
> coat protein shell.  How do I name these 180 chains in my input PDB
> file for PROTIN/REFMAC? Do the programs treat the chain identifiers as
> case sensitive characters that would allow chain A to be recognized as
> being distinct from chain a? Is it possible to use the SEGID columns
> (73-76) in place of chain ID?
> 
> I will appreciate any help
> 
> Sugoto


 Aaagh
With difficulty! 
 It is a case for using SEGID certainly..

(By the way you prob should update to refmac5 which doesnt depend on
PROTIN)

 Chain IDS can use upper and lower case, but even that doesnt solve your
problem..

 It is going to need work!
In the mean time - how long is each chain? You can often get away with
numbering things 1 - x, 201-200+x, etc etc assuming your chain is < 200
residues..

 The NCS restraints use both chain ID and residue span, and residue
numbers can go up to 9999.

 Eleanor