[phenixbb] regarding ncs distance - .geo file

Maia Cherney chern at ualberta.ca
Sat Nov 21 08:56:18 PST 2009


Hi Pavel,
I would like to make a suggestion about the use of 
excessive_distance_limit. Instead of shutting down the refinement due to 
excessive_distance over the limit why not use it for excluding only 
those residues from NCS refinement and do the ncs refinement for the 
rest of the residues.

Maia



Pavel Afonine wrote:
> By the way, it may be worth of repeating that the .geo file contains 
> the list of all the geometry restraints used in phenix.refine 
> refinement (bonds, angles, planarities, chiralities, dihedrals, 
> non-bonded, NCS, custom defined restraints and edits), for each and 
> every atom, making it a complete foot-print of geometry restraints 
> used to obtain the final refined structure.
>
> Pavel.
>
> On 11/18/09 11:12 AM, Pavel Afonine wrote:
>> Hi Shya,
>>
>> inspect the .geo file for something like "EXCESSIVE DISTANCE" (or 
>> something similar, I don't remember exactly), and that will give you 
>> an idea by how much you exceed the default 1.5 value.
>>
>> It might be worth of looking at those atoms in NCS copies that have 
>> too large deviations between NCS copies, and if you find that it is 
>> for the reason, then you may want to exclude them from NCS.
>>
>> Good luck!
>> Pavel.
>>
>>
>> On 11/18/09 11:07 AM, sbiswas2 at ncsu.edu wrote:
>>> Hi Pavel,
>>>
>>> Whenever I run ncs using the default parameters I get the following:
>>>   The current limit is:
>>>     refinement.ncs.excessive_distance_limit=1.5
>>>   The number of distances exceeding this limit is: 364
>>>   Please correct your model or redefine the limit, e.g. with:
>>>     refinement.ncs.excessive_distance_limit=3
>>>   To disable this message completely define:
>>>     refinement.ncs.excessive_distance_limit=None
>>>
>>> It runs fine when you put refinement.ncs.excessive_distance_limit=None in
>>> the command line. My question is what would be the best distance for the
>>> program to run without this message.
>>> thanks,
>>> Shya
>>>
>>>
>>>
>>>
>>>
>>>
>>>   
>>>> Hi Raja,
>>>>
>>>> here are a few comments:
>>>>
>>>> - if you used TLS previously and then run a refinement without TLS (that
>>>> is "strategy=..." does not include "tls"), the previous TLS refinement
>>>> gets invalidated, because phenix.refine will automatically convert
>>>> ANISOU into isotropic equivalent. It says it somewhere in .log file.
>>>>
>>>> - the "run 1" looks better than the others indeed (judging by the
>>>> R-factors and bond/angles RMSDs at this resolution).
>>>>
>>>> - your original concern was the geometry problems, so using H in
>>>> refinement, as well as optimizing weights, may help fixing them. So I
>>>> would check the geometry too for all the runs below, and not only
>>>> R-factors.
>>>>
>>>> - yesterday Kendall suggested a set of good ideas to try out regarding
>>>> NCS.
>>>>
>>>> - I did not understand what you mean by "default extension of high
>>>> resolution range in PHENIX". phenix.refine uses all reflections that it
>>>> finds in your input data files, unless specified otherwise using
>>>> high/low resolution cutoffs and sigma cutoffs. phenix.refine does not
>>>> collect any additional data for you -:)
>>>>
>>>> - at 2.9A it is very likely that you still ok to refine individual ADPs
>>>> and switching to group ADP can increase R-factors. So no surprises here.
>>>> I doubt that using bulk-solvent correction and anisotropic scaling
>>>> increases the R-factors; probably you tried it in combination with
>>>> something else, and that "something else" was the cause of increased
>>>> R-values.
>>>>
>>>> - are you using the latest version of PHENIX ?
>>>>
>>>> Pavel.
>>>>
>>>>
>>>> On 11/18/09 8:47 AM, Raja Dey wrote:
>>>>     
>>>>> Hi Pavel,
>>>>>               I finished 4 runs as you suggested. See below:
>>>>> run1.
>>>>> phenix.refine 1205A-p21212.mtz nov138_001.pdb ncs_groups.params
>>>>> main.ncs=true ncs.find_automatically=false
>>>>> refinement.ncs.excessive_distance_limit=None
>>>>> xray_data.high_resolution=2.9 refinement.main.number_of_macro_cycles=5
>>>>> output.write_maps=true output.prefix=nov17
>>>>> REMARK Start: r_work = 0.2803 r_free = 0.3036 bonds = 0.012 angles =
>>>>> 1.488
>>>>> REMARK Final: r_work = 0.2438 r_free = 0.2994 bonds = 0.009 angles =
>>>>> 1.309
>>>>> b_ave=70.09
>>>>>
>>>>> run2. with wxc and wxu optimization
>>>>> phenix.refine 1205A-p21212.mtz nov138_001.pdb ncs_groups.params
>>>>> main.ncs=true ncs.find_automatically=false
>>>>> refinement.ncs.excessive_distance_limit=None
>>>>> xray_data.high_resolution=2.9 refinement.main.number_of_macro_cycles=5
>>>>> optimize_wxc=true optimize_wxu=true output.write_maps=true
>>>>> output.prefix=nov17-opt
>>>>> REMARK Start: r_work = 0.2803 r_free = 0.3036 bonds = 0.012 angles =
>>>>> 1.488
>>>>> REMARK Final: r_work = 0.2143 r_free = 0.2961 bonds = 0.032 angles =
>>>>> 3.281
>>>>> b_ave=64.71
>>>>>
>>>>> phenix.reduce may21_pdbset.pdb > may21_pdbset_h_added.pdb
>>>>>
>>>>> run3.  with hydrogen
>>>>> phenix.refine 1205A-p21212.mtz nov138_001_h_added.pdb ncs_groups.params
>>>>> main.ncs=true ncs.find_automatically=false
>>>>> refinement.ncs.excessive_distance_limit=None
>>>>> xray_data.high_resolution=2.9 refinement.main.number_of_macro_cycles=5
>>>>> output.write_maps=true output.prefix=nov17-wh
>>>>> REMARK Start: r_work = 0.2860 r_free = 0.3123 bonds = 0.085 angles =
>>>>> 1.672
>>>>> REMARK Final: r_work = 0.2381 r_free = 0.3029 bonds = 0.017 angles =
>>>>> 1.685
>>>>> b_ave=77.7
>>>>>
>>>>> run4. with both hydrogen and optimization
>>>>> phenix.refine 1205A-p21212.mtz nov138_001_h_added.pdb ncs_groups.params
>>>>> main.ncs=true ncs.find_automatically=false
>>>>> refinement.ncs.excessive_distance_limit=None
>>>>> xray_data.high_resolution=2.9 refinement.main.number_of_macro_cycles=5
>>>>> optimize_wxc=true optimize_wxu=true output.write_maps=true
>>>>> output.prefix=nov17-wh-opt
>>>>> REMARK Start: r_work = 0.2860 r_free = 0.3123 bonds = 0.085 angles =
>>>>> 1.672
>>>>> REMARK Final: r_work = 0.2447 r_free = 0.3032 bonds = 0.020 angles =
>>>>> 1.922
>>>>> b_ave=80.75
>>>>>
>>>>> It looks output from run1 is the best, adding hydrogen and optimizing
>>>>> wxc and wxu did not help much.
>>>>> I have had little better Rfree and rmsd at the end of my last run.
>>>>>
>>>>>
>>>>> You are right. the commands I used at the last stage looks weird. Before
>>>>> that run I have used
>>>>> "strategy=rigid_body+individual_sites+group_adp+tls" and also included
>>>>> bulk_solvent and scaling. The map is pretty good. But, the number of
>>>>> reflections used in the refinement was more than that in mtz file and
>>>>> that was the warning in the pdb validation summary letter. I think
>>>>> that's because default extension of high resolution range in PHENIX. So,
>>>>> I needed to run 1 macro cycle with a little lower high resolution 2.9A
>>>>> with the last refined pdb. I found those are the combination of commands
>>>>> gives the best R, Rfree and rmsd for bonds and angles. As soon as I was
>>>>> including bulk solven and scaling correction and/or b_group the values
>>>>> were increasing. Although I don't have clear explanation, but that is
>>>>> what I found. Any way these are very little differences and might not be
>>>>> so important.
>>>>>
>>>>> I fixed the problem in dna. The problem was related with the occupancy
>>>>> of the 2 alternate conformations of dna. But, I still have 8 amino
>>>>> acids' (out of 400) phy, psy  out side Ramachandran plot. Probably this
>>>>> does not mater much if I I deposite this co-ordinate in PDB.
>>>>> Thanks for all your suggestions though.
>>>>>
>>>>> Regards...
>>>>> Raja
>>>>>
>>>>>
>>>>> ----- Original Message -----
>>>>> From: Pavel Afonine <PAfonine at lbl.gov>
>>>>> Date: Tuesday, November 17, 2009 12:20 pm
>>>>> Subject: Re: [phenixbb] fixing geometry for deposition
>>>>> To: PHENIX user mailing list <phenixbb at phenix-online.org>
>>>>>
>>>>>
>>>>>       
>>>>>> Hi Raja,
>>>>>>
>>>>>>
>>>>>>         
>>>>>>>               I used the following commands at the last stage of
>>>>>>>
>>>>>>>           
>>>>>> refinement:>
>>>>>>
>>>>>>         
>>>>>>> phenix.refine 1205A-p21212.mtz nov138_001.pdb
>>>>>>>
>>>>>>>           
>>>>>> simulated_annealing=false ncs_groups.params main.ncs=true
>>>>>> ncs.find_automatically=false
>>>>>> refinement.ncs.excessive_distance_limit=None
>>>>>> main.bulk_solvent_and_scale=false strategy=rigid_body+individual_sites
>>>>>> xray_data.high_resolution=2.9 refinement.main.number_of_macro_cycles=1
>>>>>> output.write_maps=true output.prefix=nov139 --overwrite
>>>>>>
>>>>>>         
>>>>>>>           
>>>>>> The above command seems extremely weird to me for the following
>>>>>> reasons:
>>>>>> 1) Bulk-solvent correction and anisotropic scaling always has to be
>>>>>> done
>>>>>> (unless you are experimenting with fake data or these corrections
>>>>>> have
>>>>>> been already applied to Fobs, which is bad ideas anyway). By using
>>>>>> "main.bulk_solvent_and_scale=false" you turn bulk-solvent
>>>>>> correction and
>>>>>> anisotropic scaling off.
>>>>>>
>>>>>> 2) By default, phenix.refine does 3 refinement macro-cycles, but
>>>>>> often
>>>>>> (depending how far you are from the final model) this is not enough
>>>>>> for
>>>>>> refinement to converge, so increasing it to 5 or so is a good idea.
>>>>>> Doing just one macro-cycle
>>>>>> (refinement.main.number_of_macro_cycles=1)
>>>>>> does not make much sense to me. By the way, you can use shortcuts
>>>>>> like
>>>>>> "main.number_of_m=5".
>>>>>>
>>>>>> 3) You can drop this off the list since it is the default setting
>>>>>> anyway: "simulated_annealing=false".
>>>>>>
>>>>>> 4) The refinement strategy: "strategy=rigid_body+individual_sites".
>>>>>> Normally, you do the rigid body refinement at initial stages of
>>>>>> refinement when your model is poor, and not at the final run. This
>>>>>> is
>>>>>> because the rigid-body refinement can be very rude on your model:
>>>>>> bonds
>>>>>> can be broken between rigid groups since no restraints is used, for
>>>>>> example. Also, it's strange that the ADP refinement is turned off -
>>>>>> it's
>>>>>> always good to do, and at 2.8A you can still refined individual
>>>>>> ADPs.
>>>>>> Well, I'm not mention using TLS...
>>>>>>
>>>>>> So, I would modify the above command as following:
>>>>>>
>>>>>> phenix.refine 1205A-p21212.mtz nov138_001.pdb ncs_groups.params
>>>>>> main.ncs=true ncs.find_automatically=false
>>>>>> refinement.ncs.excessive_distance_limit=None
>>>>>> xray_data.high_resolution=2.9 output.write_maps=true
>>>>>> output.prefix=test
>>>>>> --overwrite
>>>>>>
>>>>>> and try running it as is, and with adding keywords
>>>>>> "optimize_wxc=true
>>>>>> optimize_wxu=true", using a model with or w/o H riding H atoms,
>>>>>> etc...
>>>>>> what I wrote in my previous email.
>>>>>>
>>>>>>
>>>>>>         
>>>>>>> Regarding amino acids phy, psy..... I tried real space
>>>>>>>
>>>>>>>           
>>>>>> refinement/regularization in coot,
>>>>>>
>>>>>> This is not the same as what I suggested to try in my previous
>>>>>> email.
>>>>>> Anyway, I would first try the modified command above and only then
>>>>>> try
>>>>>> other suggested things.
>>>>>>
>>>>>> Good luck,
>>>>>> Pavel.
>>>>>>
>>>>>> _______________________________________________
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>>>>>> phenixbb at phenix-online.org
>>>>>> http://www.phenix-online.org/mailman/listinfo/phenixbb
>>>>>>
>>>>>>
>>>>>>         
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>>>>>       
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