Rarely do I disagree with the wit and wisdom of James Holton, but R1 is
not a property that Macromolecular World is unaware of.
R1 is just Rwork.
It's just R1 = Σ | |Fo| – |Fc| | / Σ |Fo|
However e.g. George Sheldrick's SHELXL reports it based on a 4 sig(F)
cutoff as well as on all data. Exam
Discarding weak data was not the way macromolecular refinement was
done prior to 1990. Discarding data to lower your R-value is a bad
practice now and was a bad practice back then. It is my recollection
that some people using X-plor adopted this practice, along with
discarding all low resoluti
Dear James.
What small molecule programs report often looks like:
R1 = 0.1550 for 17413 Fo > 4sig(Fo) and 0.2058 for all 23715 data
R1(Free) = 0.2208 for 1938 Fo > 4sig(Fo) and 0.2766 for all 2635 data
from a well-known small molecule program being (mis)used to refine a
protein. T
If you suspect that weak data (such as all the spot-free hkls beyond
your anisotropic resoluiton limits) are driving up your Rwork/Rfree,
then a good sanity check is to compute "R1". Most macromolecular
crystallographers don't know what "R1" is, but it is not only
commonplace but required in
Dear Michael,
Did you ask Phaser to check for all possible space groups? There are still I422
and I4 you did not mention. If the space group that came out of Phaser is
different from the space group used for processing, subsequent refinement
programs may use the wrong space group from the proce
