Re: [ccp4bb] translation of atom sites and maps

- 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: problem running DISTANG
From: Xie Jiabao xie {- dot -} jiabao {- at -} YAHOO {- dot -} COM
Date: 2008-08-06

Next message:
Subject: sketcher and nitrogen in rings
From: Jan Abendroth jan {- dot -} abendroth {- at -} GMAIL {- dot -} COM
Date: 2008-08-06

Subject: Re: translation of atom sites and maps
From: Bernhard Rupp bernhardrupp {- at -} SBCGLOBAL {- dot -} NET
Date: 2008-08-06

I think you can find this also from the tables directly.
The origin statement says

Origin at 23

i.e. on *any* special position with PGS 23

there are 4 of them in F23: 4a, 4b, 4c, 4d.

They are listed at the end of the position table and
of course agree with what Ian derived.

BR

-----Original Message-----
From: CCP4 bulletin board [mailto:CCP4BB@JISCMAIL.AC.UK] On Behalf Of Ian
Tickle
Sent: Wednesday, August 06, 2008 6:53 AM
To: CCP4BB@JISCMAIL.AC.UK
Subject: Re: [ccp4bb] translation of atom sites and maps

Hi David

No F23 has 4 alternate non-equivalent origins (i.e. invariant amplitudes,
different phases):

(0, 0, 0)
(1/4, 1/4, 1/4)
(1/2, 1/2, 1/2)
(3/4, 3/4, 3/4)

You can of course have other combinations of these by adding any of the
4 F-centring translations.

You can work this out from this table:
http://www.ccp4.ac.uk/html/cheshirecell.html

For F23 (in the list on the right, 2 lines from the bottom) you see that the
Cheshire space group is I-centred (Im3m in the 1st column) and the Cheshire
cell is (a/2, b/2, c/2). The lattice translation gives the origin at (1/2,
1/2, 1/2) and the combination of this with the I centring of the Cheshire SG
gives the origins at (1/4, 1/4, 1/4) & (3/4, 3/4, 3/4).

HTH!

CCP4bb navigation

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

Previous message:
Subject: problem running DISTANG
From: Xie Jiabao xie {- dot -} jiabao {- at -} YAHOO {- dot -} COM
Date: 2008-08-06

Next message:
Subject: sketcher and nitrogen in rings
From: Jan Abendroth jan {- dot -} abendroth {- at -} GMAIL {- dot -} COM
Date: 2008-08-06