Re: [ccp4bb]: Matthews Parameter

[Bart Hazes <bart.hazes@ualberta.ca>]

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Rufer, Arne {PRBD~Basel} wrote:
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> Dear collegues,
> I'm currently dealing with a dataset for which the Cell Content Analysis tool implemented in CCP4i gives a value of 1.6. Has anybody ever encountered such a low solvent content (i.e., 24.3 %)? Is there any statitistics on this subject in the literature? Any suggestions are wellcome (I already considered crystallization of a fragment).
> Thanks,
> Arne
> 

That is indeed a very low value. Does the crystal diffract like crazy? 
If not you may have a problem. If your crystal is twinned with a near 
50% twin fraction you can see extra symmetry in the diffraction pattern 
that may make you believe that you have higher symmetry than is real. In 
that situation Vm gets underestimated by a factor of two (assuming diad 
twin symmetry). Check for twinning to see if this is your problem.

Bart

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Bart Hazes (Assistant Professor)
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