[RASMB] Oligomerization of small peptides (20-30 aa)...

[Peter Edward Prevelige Jr]

Our best uses to date have been on relatively large protein oligomers  
and include:

Determination of subunit stoichiometry in large complexes ( measured  
mass of complex within 200-300 da of calculated mass for a 360 KDa  
dodecamer is very reassuring)

Detection of mixtures of oligomers - 12mer "contaminated" with 10%11mer

Determination of off rates for very stable complexes (sub nanomolar)  
via isotopic mixing

Determination of ligand binding stoichiometry/cooperativity/ 
association constant via titration and mass measurements

Peter Prevelige

Sent from my iPhone

On Feb 10, 2010, at 8:34 AM, "Tom Laue" <Tom.Laue at unh.edu> wrote:

> Hi-
> MS for looking at peptide oligomerization can be very powerful and,
> under correct conditions, quantitative. It depends on the system you  
> are
> examining (is the solvent compatible with ES-MS) and the question you
> are asking (detecting oligomers is relatively simple, extracting
> dissociation constants may not be).
> The concern always is that the dissociation constant is a system
> parameter, and system perturbation is inherent in conducting MS. With
> the appropriate controls it can work. Usually the controls include a
> demonstration that for a model peptide (i.e. the native peptide
> structure) the ES-MS provides equivalent estimates of association
> energies as an independent solution method. Then ES-MS is used to
> characterize the relative association energies for peptides that are
> similar to the model peptide.
> Best wishes,
> Tom
>
> Schoenfeld, Hans-J. wrote:
>> Dear RASMB colleagues,
>> the methods of choice to characterize peptide oligomerization in
>> solution so far in my view were AUC in equilibrium mode or static
>> light scattering methods...
>> Recently, I heart about attempts to investigate peptide
>> oligomerization as function of pH, buffer composition, etc. by
>> electron spray mass spectroscopy. Are there opinions around about how
>> MS methods in doing that compare to the more classical methods as
>> mentioned above. I can hardly believe how MS could work without
>> significantly influencing weak interactions or change equilibria...
>> Thanks for any comment on that topic.
>> Best regards,
>> Hans-Joachim.
>> Ps: also grateful for any literature of review references on this  
>> topic...
>>
>> ============================================
>> Dr. Hans-Joachim Schönfeld
>> F. Hoffmann-La Roche Inc.
>> Preclinical research, B93/5.44
>> CH-4070 Basel
>> Switzerland
>>
>> Tel. (+41) 61 688 28 95
>> Fax. (+41) 61 688 90 60
>> _mailto:hans-j.schoenfeld at roche.com_
>>
>> --- 
>> ---------------------------------------------------------------------
>>
>> _______________________________________________
>> RASMB mailing list
>> RASMB at rasmb.bbri.org
>> http://rasmb.bbri.org/cgi-bin/mailman/listinfo/rasmb
>>
>
> -- 
> Department of Biochemistry and Molecular Biology
> University of New Hampshire
> Durham, NH 03824-3544
> Phone: 603-862-2459
> FAX:   603-862-0031
> E-mail: Tom.Laue at unh.edu
> www.bitc.unh.edu
> www.camis.unh.edu
>
> _______________________________________________
> RASMB mailing list
> RASMB at rasmb.bbri.org
> http://rasmb.bbri.org/cgi-bin/mailman/listinfo/rasmb