Re: [ccp4bb] truncate ignorance

- Protein crystallography

Main steps:

- Protein purification
- Crystallisation

Special:

- Programs for crystallography
- X-ray detectors

Basic tutorials:

   - Chemistry
   - Protein
   - Peptide
   - Amino Acids

Xtal community:

- CCP4BB

CCP4bb navigation

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

Previous message:
Subject: Re: truncate ignorance
From: William Scott wgscott {- at -} CHEMISTRY {- dot -} UCSC {- dot -} EDU
Date: 2008-09-08

Next message:
Subject: Re: truncate ignorance
From: Jacob Keller j-keller2 {- at -} MD {- dot -} NORTHWESTERN {- dot -} EDU
Date: 2008-09-08

Subject: Re: truncate ignorance
From: Jon Wright wright {- at -} ESRF {- dot -} FR
Date: 2008-09-08

Borhani, David wrote:
> ...
> but I think pretty much everyone has converged on using it for the
> past many years.

Many small molecule crystallographers seem to refine on intensity and so
avoid need this procedure. Towards the end of the recent thread "Wilson
plot from truncated.mtz" it had seemed like this forum was starting to
see that light?

In short - if your observations are supposed to be noisy in the
"plus_or_minus sigma" sense then the peaks which are much less than the
sigma should come out negative almost half of the time. Truncate would
appear to be for the case where you want an estimate of the true
magnitude of the structure factor, "F", and not your experimental data.

Jon

CCP4bb navigation

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

Previous message:
Subject: Re: truncate ignorance
From: William Scott wgscott {- at -} CHEMISTRY {- dot -} UCSC {- dot -} EDU
Date: 2008-09-08

Next message:
Subject: Re: truncate ignorance
From: Jacob Keller j-keller2 {- at -} MD {- dot -} NORTHWESTERN {- dot -} EDU
Date: 2008-09-08