Re: [ccp4bb]: B-factor and resolution

[Peter Burkhard <Peter.Burkhard@unibas.ch>]

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Edward Berry wrote:
> 
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> 
> Gerard \"CD\" Kleywegt wrote:
> > well, i had a quick look at the data stored in QDB
> > (gjk, acta cryst d52, 842-857) which shows that
> > for 435 structures the corr coeff between resolution
> > and average b is only 0.06, i.e. insignificant
> > On Thu, 4 Jan 2001, Yu Wai Chen wrote:
> >
> > > Dear all,
> > >
> > > Does any one know if there is any correlation between the overall
> > > B-factor of a structure in relation to its resolution?  Are there any
> > > publications on this topic?
> 
> I believe there must be very good correlation between the actual
> (as opposed to reported) B-overall of a crystal and the resolution
> to which it diffracts. After all, "the crystal was well-ordered
> to 3 A" is almost synonymous with "the crystal diffracted to 3 A",
> and the B-factor is a measure of order.

To me this sounds a little bit too simple. The resolution limit is
not simply determined by the B-factor, as Ed suggests. Small crystals
collected at on an inhouse source might diffract only to 3.0A while
still being well ordered (i.e. low B-fators). From a large crystal
using synchrotron radiation you may be able to reach 2.0A even though
it has higher B-factors.
Actually, this is really nothing new but it may (apart from the
refinement-
program artefacts) explain the low correlation between B-fators and
resolution.

Pete 

___________________________________________________________________________

Dr. Peter Burkhard
Abteilung Strukturbiologie
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