Re: [ccp4bb]: Protein-DNA complex

[<gb10@globalphasing.com>]

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Dear Philippe,

     The problem you mention might be caused by the fact that the DNA in 
your signature is left-handed.


     With best wishes,

          Gerard.

--
Original message from Philippe BENAS:
> 
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> 
> Hi Folks,
> 
> There is a problem trying to evaluate the presence of nucleic acids by
> gel experiments.
> If for some reasons the crystals are not well washed enough, you could
> see a band corresponding to your DNA, but bound to the surface of the
> crystals (I have a very good example of that on HIV-1 RT/RNA
> complexes...).
> So, to solve this problem you will have to quantify your bands and the
> volume your crystals (same problem with an end labelling of your NA). At
> this point, it seems easier to me to take a UV absorbance spectrum and
> use the absorbance profile of the protein alone and the DNA alone to
> deconvolute your experimental profile. I also have a very good example
> of that on the same subject. In addition, you also get the stoechiometry
> of the complex and a crude estimate of the number of molecules per au.
> The only caveats are to have i) crystals of rather simple shape and ii)
> a camera that is resolutive enough to get a precise estimate of the
> volume (and have a 5 uL UV cuvette).
> 
> Philippe
> -- 
> _______________________________________________________________________
> Philippe BENAS
> 
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-- 

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