[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: [ccp4bb]: B-factor and resolution
*** For details on how to be removed from this list visit the ***
*** CCP4 home page http://www.dl.ac.uk/CCP/CCP4/main.html ***
Edward Berry wrote:
>
> *** For details on how to be removed from this list visit the ***
> *** CCP4 home page http://www.dl.ac.uk/CCP/CCP4/main.html ***
>
> 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
Klingelbergstr. 70
CH-4056 BASEL, Switzerland
Phone: ++41 61 267 20 91
Fax: ++41 61 267 21 09
E-mail: Peter.Burkhard@unibas.ch
web: http://www.biozentrum.unibas.ch/burkhard