lesburg at a.chem.upenn.edu
Wed Sep 20 13:37:20 EST 1995
I was wondering today about very high resolution crystal structures.
There are, in the PDB, many high resolution structures. Of these
structures, there seem to be a disproportionate number solved at 1.54 A
resolution. This value (due to its relatively high prevalence)
seems related to the wavelength of the radiation used to solve the
structure (Cu Ka=1.5418 A). When the number of structures solved is
plotted against resolution, there seems to be a 'bell-curve' effect
between 1.57 A and 1.51 A with the peak centered at 1.54 A.
However, isn't the maximum resolution for Cu Ka radiation actually
very close to *half* the wavelength (Ref: Stout & Jensen, 2nd ed., p37)?
So, could people be arbitrarily cutting off their data at 1.54 A when
it might actally diffract to 1.50 A or better?
I would appreciate any sort of comments that would put my thinking on
the right track. Thanks.
lesburg at chem.upenn.edu
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