Re: [ccp4bb]: Protein/nucleic acid crystallization

[xin chen <xtalklear@yahoo.com>]

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Spermine has been known to facilitate DNA bending and
condensation (refer to article by Tippin DB et al
"Nine polymorphic crystal structures of d(CCGGGCCCGG),
d(CCGGGCCm5CGG), d(Cm5CGGGCCm5CGG) and
d(CCGGGCC(Br)5CGG) in three different conformations:
effects of spermine binding and methylation on the
bending and condensation of A-DNA." J Mol Biol. 1997
Apr 18;267(5):1171-85.).  It's possible that the high
spermine involved in your case is required for crystal
packing instead of competing with protein binding. I
wouldn't worry about it too much at this point unless
your crystal is shown to consist of DNA only by other
biochemical/biophysical methods.
Good luck!

Xin Chen

*******************************
XIN CHEN
Aventis Pharmaceuticals
1041 Route 202-206
P.O. Box 6800, Mailcode N103A
Bridgewater, NJ 08807
Tel  (908) 231-3366
Fax (908) 231-3576
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--- court@mrc-lmb.cam.ac.uk wrote:
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> visit the  ***
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> 
> I'm chasing a condition from a sparse matrix screen
> for a protein/DNA 
> complex. Things are going well but I'm worried about
> an unusually high 
> spermine concentration. Complex crystals grow
> between 10mM and 15mM 
> spermine.
> 
> Does anyone have any experience of protein/nucleic
> acid crystals at this or 
> even higher level of spermine?
> 
> As far as I can tell the spermine does not
> dissociate the complex and drops 
> containing just the oligo do not have crystals.
> 
> Thanks in advance,
> 
> Rob Court
> 
> Robert Court
> 
> Structural Studies
> MRC Laboratory of Molecular Biology
> Hills Road
> Cambridge
> CB2 2QH
> UK
> 
> Tel. +44 (0)1223 402444
> Fax. +44 (0)1223 213556
> 


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