[RASMB] Sedimentation coefficient of human serum albumin monomer and good protein standard with well established s value

[Arthur Rowe]

Greetings, everyone

This issue is an obvious signal for a old hobby-horse of mine to have a run
out in the field.

The concept of a standard s value for some protein (or whatever) is a lovely
idea. But two things are involved: one of them is getting suitable standard
solute(s), which may be possible, say RNAse as one idea; but the the other
thing is getting all the parameters to be either known or measurable. I have
discussed in some detail all the factors which limit the precision and the
accuracy of s values (Errington & Rowe 2003). The most serious matter by a
way is the rotor temperature, and this is not known in the XL-I/A to the
precision needed to take advantage of the precision inherent in the
definition of s values by SV analysis.

However, if you are prepared, or someone is, to check out the absolute
temperature of a rotor using Walter Stafford's colorimetric method, then it
just needs one definition of the 'real' s values for one or two well known,
stable and monomeric proteins^ for everyone else to be able to benefit.
Volunteers?

Seasonal wishes to all

Arthur

^or something else, such as small colloidal gold spheres, from a batch
available to all. They give beautiful SV diagrams. Or apoferritin - always
has some dimers present, but they are resolved away, so who cares?
--
*******************************************************
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
Fax:        +44 (0)115 951 6157
email:      arthur.rowe at nottingham.ac.uk
Web:        www.nottingham.ac.uk/ncmh/business
*******************************************************



N Errington, A J Rowe (2003)  "Probing conformation and conformational
change in proteins is optimally undertaken in relative mode" European
Biophysics Journal 32 (5) 511-517




Hi! Everyone
We are looking for some "protein standard" to qualify our sedimentation
velocity method. We think that HSA may be a good candidate for the
standard. Does anyone know the sedimentation coefficient of human serum
albumin monomer (corrected for buffer density and viscosity as well as
vbar)? Some literatures said HSA has a sedimentation coefficient of 4.6 s,
this is significantly higher than the value of the monomer sedimentation
coefficient of HSA I got by analyzing the SV data of Sigma HSA using C(s)
model. The C(s) profile of this Sigma HSA showed that the product contains
about 80% monomer, 17% dimer and 3% trimer. So I guess the 4.6 s value
reported in some literatures is the weight average apparent s value of the
HSA monomer, dimer and trimer (or even some oligomers) in the sample
instead of the apparent s value of HSA monomer. Therefore it will be very
helpful for me if anyone can tell me the accurate s value of HSA monomer.
Also the suggestions for better protein standard (better commercial
available) with a well established s value will be very helpful.

Thanks!

Yiming


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