*Subject: *[ccp4bb] Problem with getting Rfree and Rf down
Hi every one
I have some crystals in the space group P3121. I collect 180 frames of
data.
My crystals do not diffract better than at most 2.0 angstrom, but the Rf
barely goes below 23%,
and Rfree also remains somewhere between 28-33%. I
Le 24/01/12 21:18, Dale Tronrud a écrit :
On 01/24/12 11:52, Miguel Ortiz Lombardia wrote:
El 24/01/12 18:56, Greg Costakes escribió:
Whoops, I misspoke... I meant Rsym and Rmerge increase with higher
redundancies.
But then suppose that one merges data from a crystal that is degrading
Trigonal space groups have a choice of two arbitrary settings.
Were all those 180 frames collected in one pass? What were the
integration statistics?
What was the phasing method? Did you have a pre-existing structure*,
molecular replacement, anomalous, or what?
* This is the one I am
: Sam Arnosti meisam.nosr...@gmail.com
To: CCP4BB@JISCMAIL.AC.UK
Sent: Monday, January 23, 2012 4:48:50 PM
Subject: [ccp4bb] Problem with getting Rfree and Rf down
Hi every one
I have some crystals in the space group P3121. I collect 180 frames of data.
My crystals do not diffract better than
On 24 January 2012 15:23, Greg Costakes gcost...@purdue.edu wrote:
It would seem that you have a large model bias. Rule of thumb is to keep
R/Rfree within 5% of each other. If you find that the numbers
are separating during refinement you need to reduce the weighting factor
(dont use
*Subject: *[ccp4bb] Problem with getting Rfree and Rf down
Hi every one
I have some crystals in the space group P3121. I collect 180 frames of data.
My crystals do not diffract better than at most 2.0 angstrom, but the Rf
barely goes below 23%,
and Rfree also remains somewhere between 28-33
...@purdue.edu
Cc: CCP4BB@JISCMAIL.AC.UK
Sent: Tuesday, January 24, 2012 12:43:43 PM
Subject: Re: [ccp4bb] Problem with getting Rfree and Rf down
Is this observation about redundancies a general rule that I missed?
It seems rather surprising to me. What have results have others seen?
Dale Tronrud
:43 PM
*Subject: *Re: [ccp4bb] Problem with getting Rfree and Rf down
Is this observation about redundancies a general rule that I missed?
It seems rather surprising to me. What have results have others seen?
Dale Tronrud
On 01/24/12 07:23, Greg Costakes wrote:
snip...
Higher
**
*From: *Dale Tronrud det...@uoxray.uoregon.edu
*To: *Greg Costakes gcost...@purdue.edu
*Cc: *CCP4BB@JISCMAIL.AC.UK
*Sent: *Tuesday, January 24, 2012 12:43:43 PM
*Subject: *Re: [ccp4bb] Problem with getting Rfree and Rf down
Is this observation
Hi every one
I have some crystals in the space group P3121. I collect 180 frames of data.
My crystals do not diffract better than at most 2.0 angstrom, but the Rf barely
goes below 23%,
and Rfree also remains somewhere between 28-33%. I have tried to refine my data
as much as I can.
I do not
These R-values are reasonable:
http://xray.bmc.uu.se/gerard/supmat/rfree2000/plotter.html
On Mon, 2012-01-23 at 21:48 +, Sam Arnosti wrote:
Hi every one
I have some crystals in the space group P3121. I collect 180 frames of data.
My crystals do not diffract better than at most 2.0
Hi Sam,
some obvious questions:
1-Space group right? ( i´d say so from your R values...)
2-Is your data good throughout all of the 180 frames? whats Rsym if take only
100?
3-how good/complete is model? Missing parts, residues, base pairs??
4-evaluate your refinement strategy...
HTH
12 matches
Mail list logo
