Quick navigation:        Home   |    Site Map   ||    References   |    Biography   ||    Copyright   |    Other copyright   |    Contact us   |   
Protein structure
 

Re: [ccp4bb] question about processing data
 

Basic tutorials: 		 
 

CCP4bb navigation

CCP4bb <-- 2008 <-- March 2008 <-- 17 March 2008
Previous message:
Subject: Re: question about processing data
From: Melody Lin xtalin2007 {- at -} GMAIL {- dot -} COM
Date: 2008-03-17 		Next message:
Subject: Re: Missing reflections
From: Ian Tickle I {- dot -} Tickle {- at -} ASTEX-THERAPEUTICS {- dot -} COM
Date: 2008-03-17


Subject: Re: question about processing data
From: Partha Chakrabarti ppchak {- at -} GMAIL {- dot -} COM
Date: 2008-03-17
Looks ok I guess.. for the highest shell, if Rmerge is less than 0.45
and I/sigma is about 2, it is worth a try.. as James said,
completeness might be from why it is incomplete.. is it something like
C2?

experts might tell us more..
Best, Partha

On Mon, Mar 17, 2008 at 11:03 AM, Melody Lin wrote:
> well, redundancy for the highest shell is 4.8, I/sigma is 3, Rmerge for
> overall is 0.08 for highest shell is 0.336. I/sigma and Rmerge don't seem
> quite nice...
>
> thanks.
>
>
>
> On Mon, Mar 17, 2008 at 11:51 AM, Partha Chakrabarti
> wrote:
>
> > Hi Melody,
> >
> > There was a nice discussion in this year's ccp4 study weekend. In
> > general, one needs to consider several factors.. If you were at 3A, or
> > low symmetry, you would of course try to get the maximum out of it, on
> > the other hand, there are requirements for experimental phasing.. in
> > general, judge it from:
> >
> > 1. Completeness
> > 2. Redundancy
> > 3. I / Sigma
> > 4. R merge statistics
> >
> > Not just one of them. If you are pushing it too far, you will see the
> > effect in later refinement step..
> > With 74% completeness, how does the other parameters look like?
> >
> > HTH, Partha
> >
> >
> >
> >
> >
> > On Mon, Mar 17, 2008 at 10:06 AM, Melody Lin wrote:
> > > Hi all,
> > >
> > > I have always been wondering... for a data set diffracting to say 2.15
> > > Angstrom but in the highest resolution shell (2.25-2.15) the
> completeness is
> > > 74%, should I use merge all the data and call it a 2.15 A dataset or I
> > > should cut the data set to say 2.25 A where the highest resolution shell
> has
> > > better completeness (>85%)? What is an acceptable completeness value for
> the
> > > highest resolution shell?
> > >
> > > Thank you.
> > >
> > > Best,
> > > Melody
ProteinCrystallography.org: Copyright 2006-2007 by Quid United Ltd