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[ccp4bb] FW: [ccp4bb] Different chains in the dimer
 

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CCP4bb <-- 2008 <-- February 2008 <-- 08 February 2008
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Subject: Re: an over refined structure
From: Axel Brunger brunger {- at -} STANFORD {- dot -} EDU
Date: 2008-02-08 		Next message:
Subject: Re: an over refined structure
From: price {- at -} UCHICAGO {- dot -} EDU price {- at -} UCHICAGO {- dot -} EDU
Date: 2008-02-08


Subject: FW: Different chains in the dimer
From: "Skrzypczak-Jankun, Ewa" Ewa {- dot -} Skrzypczak-Jankun {- at -} UTOLEDO {- dot -} EDU
Date: 2008-02-08
Have you done both experiments at the same temperature? If cryo - have you used the same cryoprotectant?
same ionic strength? Did mutations cause changes in the surface charge distribution/hydrophobic/hydrophilic/ pi...pi interactions - if yes how it can effect quaternary structure of native. Do mutations in the model of that crystal and take a close look at the interfaces
Look at Acta Cryst. 2006, D62, 766- to see discussion about effect of freezing

In general if it is an external flexible loop I would be neither surprised nor worried, if different in the "rigid" core you need to seek explanation. Withdrawal/addition of water molecules causing tautomeric changes in Pro (from trans to cis peptide?) and as a result a shift of some fragment? It is known to happen and can move a domain.
Good luck - ESJ

________________________________________________________________________________

Dr. Ewa Skrzypczak-Jankun Associate Professor
University of Toledo e-mail: Ewa.Skrzypczak-Jankun@Utoledo.Edu
Health Science Campus Mail Stop#1091 http://golemxiv.dh.meduohio.edu/~ewa
Department of Urology Dowling Hall r. 2257
3000 Arlington Ave. phone 419 383 5414
Toledo OH 43614 fax 419 383 3785
_________________________________________________________________________________


________________________________

From: CCP4 bulletin board on behalf of Chavas Leo
Sent: Fri 2/8/2008 1:49 PM
To: CCP4BB@JISCMAIL.AC.UK
Subject: Re: [ccp4bb] Different chains in the dimer


Dear Yang,



Thanks for the reply. Both are P21. Point mutant. MR solved the mutant using native as a model.


What about the crystal contacts of the region that changed then? Is it different in "native" and "mutant" forms? Both space groups are the same, but what about the cell dimensions? Again, the packing here might be of importance. Have a look at the neighboring molecules and how the act on the varying region. Also, how different is this region? 1 angstrom? 10 angstrom?




BTW, what does HTH mean?


I don't know myself... everybody is using it, so I'm using it as well :)

H(ope)T(his)H(elps).

Kind regards.

Leo
------------------------------------------------------------
Chavas Leonard, Ph.D.
Research Associate
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Faculty of Life Sciences
The University of Manchester
The Michael Smith Building
Oxford Road
Manchester Lancashire
M13 9PT
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Tel: +44(0)161-275-1586
e-mail: Leonard.Chavas@manchester.ac.uk
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