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

Re: [ccp4bb] space group problem
 

Basic tutorials: 		 
 

CCP4bb navigation

CCP4bb <-- 2008 <-- May 2008 <-- 01 May 2008
Previous message:
Subject: space group problem
From: Junyu Xiao JUNYU {- at -} UMICH {- dot -} EDU
Date: 2008-05-01 		Next message:
Subject: Re: space group problem
From: Peter Zwart PHZwart {- at -} LBL {- dot -} GOV
Date: 2008-05-01


Subject: Re: space group problem
From: Clemens Vonrhein vonrhein {- at -} GLOBALPHASING {- dot -} COM
Date: 2008-05-01
Dear Junyu,

it looks to me like you encounter a classical monoclinic feature: one
can index monoclinic always in two ways


origin


V

A' ---------------------------------- A
/ /
/ /
/ /
/ /
/ /
/ /
/ /
/ /
/________________/

C C'

One cell (A,B,C) has B coming towards you and the other (A',B',C') has
B' pointing away from you. The two axes A and A' have identical length
as have B and B'. But C' is the diagonal in the AC-plane.

In your case you can just swap the A and C axis of the C2 (to follow
the above picture) and then calculate the C' (diagonal) to 136.8.

So to summarize: these are identical cells - just different choice
of axes (and nothing to do with the C2 versus P2 choice ... I think).

Cheers

Clemens


On Thu, May 01, 2008 at 12:03:16PM -0400, Junyu Xiao wrote:
> Hi all,
>
> We run into an interesting space group problem. The same diffraction
> image can be either indexed into space group C2, with a=145, b=44,
> c=67, and beta=110.5; or space group P2 (should be P21 after
> scaling), with a=67, b=44, c=136, and beta=96.8. Both are refined ok
> during index. These two must somehow be related. Can anyone give some
> comments on that?
>
> Thanks a lot,
> Junyu
>
> =================================
> Junyu Xiao
> Department of Biological Chemistry,
> University of Michigan
>
> Lab address:
> 3163 Life Sciences Institute,
> University of Michigan,
> 210 Washtenaw Avenue
> Ann Arbor, MI, 48109-2216
> Phone: 734-615-2078
> ==================================
>
>
>

--

***************************************************************
* Clemens Vonrhein, Ph.D. vonrhein AT GlobalPhasing DOT com
*
* Global Phasing Ltd.
* Sheraton House, Castle Park
* Cambridge CB3 0AX, UK
*--------------------------------------------------------------
* BUSTER Development Group (http://www.globalphasing.com)
***************************************************************

CCP4bb navigation

CCP4bb <-- 2008 <-- May 2008 <-- 01 May 2008
Previous message:
Subject: space group problem
From: Junyu Xiao JUNYU {- at -} UMICH {- dot -} EDU
Date: 2008-05-01 		Next message:
Subject: Re: space group problem
From: Peter Zwart PHZwart {- at -} LBL {- dot -} GOV
Date: 2008-05-01


ProteinCrystallography.org: Copyright 2006-2008 by Quid United Ltd