Re: [phenixbb] phenixbb Digest, Vol 80, Issue 1

Hello, One simple thing that might be the problem: As I'm sure you know, oligosaccharides are formed via intermolecular dehydration reactions. If I understand you correctly, you built the oligosaccharide by loading the component monomers into the density in Coot and then joined them together. Whenever two sugars are joined together, three atoms are given off as a water molecule. Did you actually delete the appropriate oxygen and two hydrogens from your coordinates for each glycosidic linkage in your structure? If you didn't, then it doesn't matter whether you told Coot or Phenix that the monomers or linked, you'll still have atoms trying to occupy the same space and thus the refinement will blow them apart. Not that I have EVER made that mistake myself . . . Similar topics have come up on the Phenix BB before. For other possibly useful information, see: http://phenix-online.org/pipermail/phenixbb/2012-April/018390.html http://www.phenix-online.org/pipermail/phenixbb/2009-October/013951.html Good luck! Matthew --- Matthew J. Whitley, Ph.D. Postdoctoral Research Fellow Angela Gronenborn Lab Department of Structural Biology University of Pittsburgh School of Medicine On Wed, July 4, 2012 7:55 pm, [email protected] wrote:

Message: 14 Date: Wed, 4 Jul 2012 15:28:09 -0400 From: crystallogrphy To: PHENIX user mailing list Subject: [phenixbb] ask refinement question including an aligo as the ligand Message-ID: Content-Type: text/plain; charset="iso-8859-1"

Hi,

I want to refine my structure including a sugar oligomer as the ligand in Phenix GUI.

I first put each subunit into the density and merge them together as the oligomer in Coot. Then I merged the oligomer coordinates to the protein file. Then I run phenix.elbow to get the cif file. Finally, I run phenix.refine. However, the oligomer units were pushed away from each other. I guess I need to modify the cif file to link the oligo units together. Does anyone know how I can I do it?

thanks!