Re: [ccp4bb] Negative density around C of COO-

- 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: HKL2000 and gcc4
From: William Scott wgscott {- at -} CHEMISTRY {- dot -} UCSC {- dot -} EDU
Date: 2008-05-05

Next message:
Subject: Refmac Error
From: Kianoush ksadree {- at -} YAHOO {- dot -} COM
Date: 2008-05-05

Subject: Re: Negative density around C of COO-
From: Lijun Liu liulj {- at -} UOXRAY {- dot -} UOREGON {- dot -} EDU
Date: 2008-05-05

I believe some, may not be all, negative density may be due to the
choice of wavelength. C,O and N are not so sensitive to normally
used wavelength (1-1.54A), but S does. This is more true when you
have higher resolution and better quality data. You can estimate
this by f'.

By the way, although I am not a real supporter of "radicals from
damage", I believe that a photo-induced (here X-ray) chemical
reaction is much different from a heat-induced one. Low temperature
is not a problem. But this not for diffusion, as it is ~100% heat-
related. Please point out if I am wrong.
> This "assignment" of free radicals to damage is often made
> (flippantly) in the literature, but I feel a strong need to point
> out that there is NO EVIDENCE of a free radical diffusion mechanism
> for radiation damage below ~130K.

Lijun Liu, PhD
Institute of Molecular Biology
HHMI & Department of Physics
University of Oregon
Eugene, OR 97403
541-346-4080

CCP4bb navigation

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

Previous message:
Subject: Re: HKL2000 and gcc4
From: William Scott wgscott {- at -} CHEMISTRY {- dot -} UCSC {- dot -} EDU
Date: 2008-05-05

Next message:
Subject: Refmac Error
From: Kianoush ksadree {- at -} YAHOO {- dot -} COM
Date: 2008-05-05