[ccp4bb] Chi-by-Eye[ Highest shell standards]

- Protein crystallography

Main steps:

- Protein purification
- Crystallisation

Special:

- Programs for crystallography
- X-ray detectors

Basic tutorials:

   - Chemistry
   - Protein
   - Peptide
   - Amino Acids

Xtal community:

- CCP4BB

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CCP4bb <-- 1999 <-- November 1999 <-- 30 November 1999

Previous message:
Subject: Re: Inclusion body
From: Hongmin Li lih {- at -} WADSWORTH {- dot -} ORG
Date: 2007-03-24

Next message:
Subject: Re: Expression hosts (was:Inclusion body)
From: Artem Evdokimov artem {- at -} XTALS {- dot -} ORG
Date: 2007-03-24

Subject: Chi-by-Eye[ Highest shell standards]
From: Bart Hazes Bart {- dot -} Hazes {- at -} UALBERTA {- dot -} CA
Date: 2007-03-24

James Holton wrote:

> I generally cut off integration at the shell wheree I/sigI < 0.5 and
> then cut off merged data where MnI/sd(I) ~ 1.5. It is always easier
> to to cut off data later than to re-integrate it. I never look at
> the Rmerge, Rsym, Rpim or Rwhatever in the highest resolution shell.
> This is because R-statistics are inappropriate for weak data.

I wonder how many peopled decide their max resolution cut-off (either
during processing or by setting the detector too far away) by eyeballing
a few images. I wouldn't be surprised if the number is substantial. Has
anyone looked at the actual resolution of a data set after processing
and the first-guess resolution reported by people just looking at the
first few images. With the generally positive trend to increase
redundancy at the cost of pushing the exposure per image, the resolution
visible to the human eye may be an even poorer estimate of true resolution.

Bart

CCP4bb navigation

CCP4bb <-- 1999 <-- November 1999 <-- 30 November 1999

Previous message:
Subject: Re: Inclusion body
From: Hongmin Li lih {- at -} WADSWORTH {- dot -} ORG
Date: 2007-03-24

Next message:
Subject: Re: Expression hosts (was:Inclusion body)
From: Artem Evdokimov artem {- at -} XTALS {- dot -} ORG
Date: 2007-03-24