[RASMB] 200 nm buffer salts

[Arthur Rowe]

Hi Mark -

I am not sure what the reason is for having 0.5 M NaF in you solution, but
as Holger Strauss has said, its pretty horrible stuff. I used to use NaF/HF
as an aid to detaching platinum replicas from glass or mica, and learned to
respect its (ferocious properties).

As  regards the general issue of what one can and cannot use in the 'far uv'
region,  we do keep a file here of what buffers etc are usable, including
details of the 'modern' buffers. Looking through our scans, here are a few
comments, all of which refer to 10 mM concentration:

Tris            impossible to use
phosphate       acceptable (pyrophosphate less so)
cacodylate      good
TES, MES,CHAPS  good
CHES            particularly good
MOPS            good
glycine         usable

Of course, in most of these cases (CHES is an exception), even though the
absorption at 206 nm may be fine (0.4 or less), one can be working on a
wavelength 'hillside', with the associated problems currently being
discussed by others on RASMB.

All the same, if one has only a little bit of protein to play with, working
in the far uv can be fine. Equilibrium is possible, time derivative methods
often really good.  An example of a  study where (of necessity) all work was
done in the far uv is:

H Tharia, O.D. Byron,  A J Rowe & C Wells (1997) "Physical characterisation
and ATPase activity of 14S dynein fractions from Tetrahymena thermophylus"
J Musc Res Cell Motil   18  697-709

All best wishes - and a Happy Christmas to you and the RASMB Community !

Arthur
--
*******************************************************
Arthur J Rowe
Professor of Biomolecular Technology
NCMH Business Centre
University of Nottingham
School of Biosciences
Sutton Bonington
Leicestershire LE12 5RD   UK

Tel:        +44 (0)115 951 6156
             +44 (0)116 271 4502
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email:      arthur.rowe at nottingham.ac.uk
             arthur.rowe at connectfree.co.uk (home)
Web:        www.nottingham.ac.uk/ncmh/business
*******************************************************


> From: "Marc S. Lewis" <mslewis at helix.nih.gov>
> Date: Wed, 12 Dec 2001 17:01:38 -0400
> To: <rasmb at server1.bbri.org>
> Subject: [RASMB] 200 nm buffer salts
> 
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> To all:
> 
> I need to do some equilibrium studies on a sulfated polysaccharide at 206
> nm.  My question is whether or not 0.5 M NaF, which has good transparency
> there, will have an adverse effect on either quartz or sapphire windows in
> a run taking several days - alternatively, is there any other neutral salt
> that could be used?
> 
> Thanks -
> 
> Marc Lewis
> 
> 
> 
> Marc S. Lewis, Ph. D., Chief
> Molecular Interactions Resource
> Division of Bioengineering and Physical Science
> Office of Research Services
> National Institutes of Health
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