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Hi,
I think the reason for our erudite quibblings about how to define
resolution
is that we use the resolution as a rough indicator
of how far we can justifiably push the interpretation of our data.
Generally the arguments about resolution boil down to
something like this:
Author:
"The cofactor in the active site deviates from planarity, which
explains the increased nucleophilicity of this cofactor"
Reviewer:
"I don't think you can determine if your cofactor is flat or not
at 2.5 Ang. resolution"
Author:
"Yes I can, because I am good crystallographer and also
my 2.5 Ang is better than a usual 2.5 Ang."
Reviewer:
"No you can't"
Author"
"Yes I can!"
...
Of course resolution is a horribly inadequate way of determining
if a particular interpretation is meaningful or not.
Crystal structures of proteins that diffract well beyond 1 Ang.
routinely contain regions, which are so disordered that they
cannot be interpreted. So despite coming from a 1 Ang.
data set the reliability / accuracy of any interpretation
of that region is ZERO.
I think the real problem is the following:
We have no good way to asses the local accuracy / reliability of the
models we generate from our data.
Small molecule crystallographers rarely ever mention the
resolution of their data. Instead they quote esd. (estimated
standard deviations) for their refined parameters. This
of course requires the availability of very high resolution
data, which we as protein crystallographers usually do not have.
What is the current thinking out there for the best approach
to get something resembling esd's.
I think this would be a very nice topic for a workshop!!!!!
Cheers,
Ulrich
--
Ulrich K. Genick
Assistant Professor
Department of Biochemistry
Brandeis University, MS009
Waltham, MA, 02454
Room Kosow 108
Phone 781-736 2304
Fax 781-736 2349
Email [EMAIL PROTECTED]
