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From: Arthur Rowe <arthur.rowe@nottingham.ac.uk>
To : Dr DJ Scott <djs17@york.ac.uk>
Date: Fri, 24 Mar 2000 12:31:32 +0000
Re: radius of gyration...
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Dave -
For a simple, unsolvated sphere, the relationship is simple:
Rg = (3/5)^0.5 * (radius) = rH or Rg = 0.775*rH
Unfortunately, proteins are in general neither unsolvated nor spherical.
For spheres, the Rg (from X-ray scattering) is predominantly (but not
entirely) down to the protein component. The rH refers to all within the
surface of shear, and includes both externally bound and internally
entrained solvent. So the numerical factor in the above relationship will
always be smaller than 0.775.
For particles which are neither unsolvated nor spherical the relationship is
too complicated to generalise about. You are, as they say, comparing apples
with oranges.
All best
Arthur
*****************************************************
Arthur J Rowe
Professor of Biomolecular Technology
University of Nottingham
School of Biological Sciences
Sutton Bonington
Leicestershire LE12 5RD UK
Phone/voicemail +44 (0)115 951 6156
Phone/fax +44 (0)115 951 6156/7
email arthur.rowe@nottingham.ac.uk
arthur.rowe@connectfree.co.uk
Web http://www.nottingham.ac.uk/ncmh/business
*****************************************************
----------
>From: Dr DJ Scott <djs17@york.ac.uk>
>To: rasmb@alpha.bbri.org
>Subject: radius of gyration...
>Date: Fri, Mar 24, 2000, 12:03 pm
>
>HIa
>does anyone know the relationship between the radius of gyration (as
>determined from X-ray scattering) and the hydrodynamic radii (as
>determined from sedimentation velocity)?
>
>I have 2 values and I want to know whether they're giving me the same
>info about the same protein....
>
>thanks in advance..
>
>dave scott
>
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<FONT SIZE=3D"2">Dave -<BR>
<BR>
For a simple, unsolvated sphere, the relationship is simple:<BR>
<BR>
Rg =3D (3/5)^0.5 * (radius) =3D rH or Rg =3D 0.775*rH<BR>
<BR>
Unfortunately, proteins are in general neither unsolvated nor spherical. F=
or spheres, the Rg (from X-ray scattering) is predominantly (but not entirel=
y) down to the protein component. The rH refers to all within the surface o=
f shear, and includes both externally bound and internally entrained solvent=
. So the numerical factor in the above relationship will always be smaller t=
han 0.775.<BR>
<BR>
For particles which are neither unsolvated nor spherical the relationship i=
s too complicated to generalise about. You are, as they say, comparing appl=
es with oranges.<BR>
<BR>
All best<BR>
<BR>
Arthur<BR>
<BR>
*****************************************************<BR>
Arthur J Rowe<BR>
Professor of Biomolecular Technology<BR>
University of Nottingham<BR>
School of Biological Sciences<BR>
Sutton Bonington<BR>
Leicestershire LE12 5RD UK<BR>
<BR>
Phone/voicemail +44 (0)115 951 6156<BR>
Phone/fax +44 (0)115 951 6156/7<BR>
email arthur.rowe@nottingham.ac.uk<BR>
arthur.rowe@connectfree.co.uk<BR>
Web http://www.nottingham.ac.uk/ncmh/business<BR>
*****************************************************<BR>
<BR>
----------<BR>
>From: Dr DJ Scott <djs17@york.ac.uk><BR>
>To: rasmb@alpha.bbri.org<BR>
>Subject: radius of gyration...<BR>
>Date: Fri, Mar 24, 2000, 12:03 pm<BR>
><BR>
<BR>
>HIa<BR>
>does anyone know the relationship between the radius of gyration (as<BR=
>
>determined from X-ray scattering) and the hydrodynamic radii (as<BR>
>determined from sedimentation velocity)?<BR>
><BR>
>I have 2 values and I want to know whether they're giving me the same<B=
R>
>info about the same protein....<BR>
><BR>
>thanks in advance..<BR>
><BR>
>dave scott<BR>
><BR>
<BR>
<BR>
</FONT>
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