[RASMB] proteins in water

[Leech, AP]

Hi All,

There are some useful comments from Walt Stafford in the RASMB archive
under "low ionic strength" / "charge effects".

SV on a small protein with no buffer seems like making life very
difficult for yourself!

Cheers,

Andrew

On 20/07/2012 16:36, Lake Paul wrote:
> Carlos,
>
> If your protein is charged then you will definitely need some counter
> ions in there. That is the most obvious cause for lower than expected
> sedimentation coefficients. Here is a good paper to start with design,
> buffer considerations etc etc.
>
> Hope this helps,
>
> Lake
>
> Analytical Ultracentrifugation in the Study of Protein Selfassociation
>
> and Heterogeneous Protein-Protein Interactions
>
> Andrea Balbo and Peter Schuck
>
> */Lake N. Paul, PhD/*
>
> Biophysics Research Specialist
>
> Discovery Park - Bindley Biosciences Center Purdue University
>
> 1203 West State Street
>
> West Lafayette, Indiana, 47905
>
> 765.494.4960
>
> *_BioAnalytical Lab Website:_*
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>
> *From:*rasmb-bounces at rasmb.bbri.org
> [mailto:rasmb-bounces at rasmb.bbri.org] *On Behalf Of *Carlos Alfonso Botello
> *Sent:* Friday, July 20, 2012 11:17 AM
> *To:* rasmb
> *Subject:* [RASMB] proteins in water
>
> Dear colleagues,
>
> We are running a 10 kDa protein at concentrations 0.2-2 mg/ml *in water*
> (no buffer is present).The sedimentation coefficients that we are
> obtaining are lower than expected for the monomer (1.4 - 1.5S). Is there
> any correction of the S that we could apply to obtain the correct S20,W.
>
> Thank you in advance for your help,
>
> Carlos
>
>
>
> Dr. Carlos Alfonso
> Departamento Biologia Celular y Molecular
> Laboratorio de Interacciones Macromoleculares: Bioquímica Citomimética
> Centro de Investigaciones Biológicas, CSIC
> C/ Ramiro de Maeztu, 9.
> 28040-MADRID
> Tlfno.- 91 8373112 ext.4406-4408-4297
> Fax: 915360432.
> E-mail: carlosa at cib.csic.es <mailto:carlosa at cib.csic.es>
> *NEW lab web page:
> http://www.cib.csic.es/es/grupo.php?idgrupo=49
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-- 
Dr Andrew Leech                   *  Laboratory Head
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