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I am not 100% sure that REFMAC is sorting that out correctly, though.

I had a case recently where I tried to refine two very similar ligands binding 
to the same binding site. I tried the way Eleanor suggested and I also tried 
defining them as Alig and Blig. REFMAC doesn't complain and refines the two 
ligands, but in the part where the two ligands are identical they don't 
superimpose exactly anymore. If I refine them separately and superimpose them 
afterwards they are superimposing exactly in the parts that are identical! 

To me it looks as if the two ligands in the same site still repel each other 
but that they are kept together by the x-ray term. Is there a well documented 
example, where somebody successfully managed to refine two ligands in the same 
binding site and how (s)he defined the two ligands and created the dictionaries 
exactly?

If I try the same refinement in CNX with some patching, the two ligands 
superimpose exactly in the identical parts.

Regards
Christian

Dr. Christian Engel
Research Scientist
Structural Biology
Sanofi-Aventis
Tel.: +49 (0)69 305 12946
Fax: +49 (0)69 305 80169

Sanofi-Aventis
Industriepark Höchst
Building G865A
65926 Frankfurt am Main
Germany



-----Ursprüngliche Nachricht-----
Von: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] Auftrag von
Eleanor Dodson
Gesendet: Donnerstag, 1. Juni 2006 10:50
An: Elena Kovaleva
Cc: [email protected]
Betreff: Re: [ccp4bb]: multiple occupancy/different ligands


Just put them both in, each with partial occupancy, and 2 dictionary 
entries. REFMAC should sort it out..
  Eleanor

Elena Kovaleva wrote:

> ***  For details on how to be removed from this list visit the  ***
> ***          CCP4 home page http://www.ccp4.ac.uk         ***
>
>
> Hi,
> I wonder if there is someone out there who knows a way to trick Refmac 
> into doing simultaneous refinement of somewhat superimposable but 
> structurally different ligands (both of which partially occupy the 
> same site). For example if a substrate and an intermediate are present 
> or an intermediate and a product. Would making a library file for a 
> "macro"-ligand consisting of 2 separate parts (separate connectivity, 
> partial occupancy, etc) be a reasonable approach or is there an 
> easier/proper way to refine partially present ligands?
> Will be grateful for any suggestions.
> Thanks,
> Lena
>
> Elena G. Kovaleva, Ph.D.
> Department of Biochemistry, University of Minnesota
> 5-202 BS&BE, 312 Church St, Minneapolis, MN 55455
> Ph (612) 625-3688, Fax (612) 625-2163
>
>


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