Aggregated protein

Matt Hicks matth at epunix.biols.susx.ac.uk
Fri Oct 22 04:14:45 EST 1999


You asked the following question:
 
"but Matt how do you detect an aggregate like 
protease-inhibitor or coil-coil or cysteine bridge aggregates by light 
scattering?"

The answer is that you look at different concentrations.  A 
covalently-linked aggregate/oligomer (eg: cysteine bridge aggregates) will 
not increase in molecular weight with concentration but a 
non-covalently-linked one will.  The non-covalently-linked aggregates 
such as coiled coils will just show their native molecular weight ie that 
of the oligomeric unit (of course for coiled coils in light scattering 
one has to take into account the shape as in size exclusion 
chromatography).  Incidentally analytical centrifugation can give you 
molecular shape info as well as molecular weight by looking at the rate 
of sedimentation or the final concentration distribution respectively.

Having said all that - I agree totally with you about using size 
exclusion as a quick method and as a preparative method for the NMR 
samples which was tghe original point anyway I 'spose! Must have slipped 
into pedantic mode temporarily :)

Happy Researching

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Matt Hicks
Centre for Biomolecular Design & Drug Development
School of Biological Sciences
University of Sussex
Falmer
BN1 9QG
UK      

Tel:   +44(0)1273 678923
Fax:   +44(0)1273 678433
email: matth at biols.sussex.ac.uk                                                  
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