Normally I would recommend letting AutoSol deal with the anisotropy of your data, as it already has the capability of anisotropy correction. It is usually best to keep your "data" uncorrected, so that the "data" are not changing as you develop new interpretations of them. You can control the application of anisotropy corrections in AutoSol as you noticed with correct_aniso=True. AutoSol will apply an anisotropy correction during structure solution and map generation, and will keep your uncorrected data for refinement (an anisotropy term is automatically applied as a parameter in refinement as well).

There is a possible advantage to using the UCLA anisotropy server in that it throws away data that is weak, and it is possible that in some cases that weak data could interfere with structure solution.

If you do use anisotropy-corrected data for AutoSol I would recommend:

1. Specify a "refinement file" explicitly, and supply a file that is not anisotropy-corrected (i.e., your original data).

2. Specify "correct_aniso=False" for AutoSol (it would probably do that anyway as your corrected-data would have no anisotropy left).

AutoSol would not normally use FP or SIGFP from the data file, only F+SIGF+ F-SIGF-; however if you are supplying a "refinement file" then this file would need F and SIGFP (and you would would want to use uncorrected data there)

The NCS overlap is not an absolute scale, so greater than one is ok. The NCS correlation goes from -1 to 1, and 0.5 is ok, but not that great.

You can supply AutoBuild with a sharpened map with map_file=Mymap_coeffs.mtz and it will use this map in the first cycle of building (you might only run one cycle in this case). At 4.1 A, I would only use the helices_strands_only option in AutoBuild however, as model building at this resolution, particularly with a relatively difficult map, will not work well.

On Sep 16, 2010, at 8:23 AM, Florian Schmitzberger wrote:

Dear All,

I would have a number of Phenix related questions:

Firstly, I used the anisotropy server ( to anisotropically truncate my mtz file with anomalous signal (SAD data). My question is if the labels (for F+/F- and SIGF+/SIGF- are correctly recognized by Phenix (Autosol).

The columns labels are: F_ref for FP; QSIGF_ref for SIGFP; GF(+)pk for F(+); LSIGF(+)pk for SIGF(+), GF(-)pk for F(-); LSIGF(-)pk for SIGF(-).

It seems QSIGF and GF(+)pk/LSIGF(+)pk etc. are , but I am uncertain if it recognizes F_ref, because for the LABIN INPUT LABELS it says "NONE" for"F".

Phenix does not seem to detect the anistropy ("Not using aniso-corrected data files as the range of aniso b is only 19.52 and 'correct_aniso' is not set); so I suppose I should use the correct_aniso=True keyword.

Secondly, what are good values for the evaluation of the NCS mask and NCS averaging Resolve is using in Phenix; NCS overlap values (e.g. in my case 1.1) and NCS_CORR (in my case 0.52) in the "resolve.scores" file. Does an NCS overlap value of greater than 1 make sense?

I am working with a (anisotropic) dataset with 4.1/4.5 A resolution, 78 % solvent content, 2-fold NCS; Perhaps a naive question: It is not possible to use B-factor sharpened maps for autobuilding with Phenix Autobuild is it?

Thank you for any comments!

Regards,

Florian
-----------------------------------------------------------
Florian Schmitzberger
Biological Chemistry and Molecular Pharmacology
Harvard Medical School
250 Longwood Avenue, SGM 130
Boston, MA 02115, US
Tel: 001 617 432 5602

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