Re: [o-info] Re: [ccp4bb]: Disulfide bridge

["Eleanor J. Dodson" <ccp4@ysbl.york.ac.uk>]

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deh22@cornell.edu wrote:
> 
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> 
> Thanks for all your quick responses!
> 
> Here are a few details (these are unrefined measurements):
> 
> S-?-S angle = 94.2
> S1-? distance = 2.88 A
> S2-? distance = 2.74 A
> 
> I purified with a cobalt-affinity column.  That is the only time the
> protein had contact with a heavy metal (other than sodium...), so I
> doubt it is mercury.
> 
> The putative metal position has density showing up in an fo-fc map at a
> sigma level greater than 11.
> 
> The problem with a metal there is that there are no water molecules
> around for coordination.  The cysteines are on the surface of the
> protein, but there is no fo-fc density for waters.  It is near (~5 A) an
> aromatic ring in a bound inhibitor.
> 
> Thanks,
> Darrell
> 
Try doing a DANO map - if it is a metal it probably has some anomalous
signal..
Eleanor

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Eleanor J.Dodson, York Structural Biology Laboratory,
                  Chemistry Department, 
                  University of York, Y01 5DD Heslington, U.K.
Tel: Work: +44 (1904) 32 82 53  Home +44 (1904) 42 44 49
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