[3dem] adsorption problems?

[Reinhard Rachel]

Hi Michael,
this might be a problem of "adsorption" to (Carbon coated? hydrophilized?) surfaces / grids. 
But, more likely, you have a biological / biochemical 'phenomenon' - is it possible that this "single subunit" acts to stabilize the whole complex? Have you tried other means for separation (not only gradient centrifugation, but: native gel electrophoresis, or any chromatography)? And, you may combine gradient centrifugation with a mild fixation step (GRAFIX; Kastner et al, in Nature Methods - 5, 53 - 55 (2008) Published online: 23 December 2007; | doi:10.1038/nmeth1139 ) 
You even may try to do a quick chemical fixation (0.1 to 1% GA; 5 min) before you apply your sample onto the grid. And, the stability of the whole complex +/- subunit may depend and vary on the pH: do you only use UAc, or did you try another negative staining solution (PTA or whatsoever)? 
lots of things to consider. 
kind regards,
Reinhard

-- 
Prof. Dr. Reinhard Rachel
University of Regensburg
Centre for EM / Anatomy
Faculty of Biology & Preclin. Med.
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