[ccp4bb]: Refmac5 Make H All

[David Buckler <buckler@cabm.rutgers.edu>]

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Dear All,

I am using Refmac5 through CCP4I 4.1.1 and am seeking advice on using the option
Make H All.

I note that Make H All is the default, but the documentation suggests using this
toward the end of refinement and only with high resolution data.

In my case, near the final stages of refinement with a 1.50 A dataset, I have
applied Make H All for several cycles and reached R=18.4 and Rfree=21.6.  Using
this same model and doing a single round of refinement from it with Make H No
results in increases to R=19.6 and Rfree=22.3.

Here are a few specific questions:

1. Is Make H All actually increasing the number of fitting parameters ("riding
positions" suggests to me "no")?
2. Can anyone provide specific suggestions for when to use this option in terms
of data resolution -- or other general guidelines?
3. If my above observation about effect on R is general, is it more proper to
report the R's for a final refinement run with Make H No since H coordinates are
not in the final model?

Thanks in advance for help.

--

David R. Buckler

CABM/UMDNJ
679 Hoes Lane
Piscataway, NJ  08854
phone: (732) 235-5164
fax:   (732) 235-5289
e-mail: buckler@cabm.rutgers.edu
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