[RASMB] peak in sedimentation velocity scans at high protein conc.

[Robert Gilbert]

This schlieren phenomenon is I think the one described by
Helmut Coelfen and Steve Harding in Progr. Colloid. Polymer
Sci. (1995) 99, 167-186, and observed by us also (Mavaddat et
al. (2000) JBC 275, 28100-28109).

Rob Gilbert


---- Original message ----
>Date: Fri, 28 Oct 2005 11:05:50 -0500
>From: "John Correia" <jcorreia at biochem.umsmed.edu>  
>Subject: Re: [RASMB] peak in sedimentation velocity scans at
high protein conc.  
>To: <Norbert.Muecke at dkfz-heidelberg.de>, <RASMB at server1.bbri.org>
>
>   RASMBers
>    
>   We too have seen this phenomena with a high MW
>   protein that forms a sharp boundary early in the
>   run.  The high gradient deflects light out of the
>   optical path.  This has been described in print, I
>   think in a German meeting proceedings.  With the
>   Model E high gradients during CsCl density gradient
>   runs (the Meselson Stahl experiment) required
>   refocusing of the optics to keep the light in the
>   optical track.  Not currently possible with the
>   current XLA design.
>    
>
>   >>> "Norbert Muecke"
>   <Norbert.Muecke at dkfz-heidelberg.de> 10/28/05 6:28 AM
>   >>>
>   Hi,
>   I have done some velocity runs at high protein conc.
>   (up to 6g/l).
>   A new peak within the boundary could be observed.
>   I have attached the scans of three different
>   concentrations.
>   Absorbance was measured at 284nm.
>   Any idea of how to explain that phenomena would be
>   appreciated.
>
>   Best regards
>   Norbert
>
>   Division Biophysics of Macromolecules, B040
>   German Cancer Research Center (DKFZ), TP3
>   Im Neuenheimer Feld 580
>   D-69120 Heidelberg, Germany
>________________
>_______________________________________________
>RASMB mailing list
>RASMB at rasmb.bbri.org
>http://rasmb.bbri.org/mailman/listinfo/rasmb


--------------------------------------
Dr Robert J. C. Gilbert
Fellow and Tutor in Biochemistry and Senior Dean of Arts, 
Magdalen College, Oxford, OX1 4AU, UK
Tel.: (+44) - 1865 - 276070

Royal Society University Research Fellow and University Research Lecturer, 
Division of Structural Biology, The Henry Wellcome Building for Genomic Medicine, 
University of Oxford, Roosevelt Drive, Oxford, OX3 7BN
Tel:. (+44) - 1865 - 287535 FAX: (+44) - 1865 - 287547