Journal
JOURNAL OF BIOLOGICAL CHEMISTRY
Volume 277, Issue 41, Pages 38921-38929Publisher
AMER SOC BIOCHEMISTRY MOLECULAR BIOLOGY INC
DOI: 10.1074/jbc.M206060200
Keywords
-
Categories
Funding
- NIGMS NIH HHS [GM-42762] Funding Source: Medline
Ask authors/readers for more resources
The subunit exchange of the small heat shock proteins (sHSPs) PsHSP18.1 from pea and TaHSP16.9 from wheat has been monitored in real-time using nanoelectrospray mass spectrometry. By preserving the noncovalent interactions between subunits in the mass spectrometer, we show that these proteins are dodecameric. After mixing PsHSP18.1 and TaHSP16.9, a distribution of heterododecamers is formed. A comparison with spectra obtained from statistical modeling demonstrates that after equilibration the distribution of these heterocomplexes is governed by the starting ratio of the two components rather than an inherent preference for certain stoichiometries. This finding suggests that the two different sHSP subunits interact in a very similar manner. Following the kinetics of this reaction by mass spectrometry reveals that exchange proceeds via sequential incorporation of subunits with dimeric species being the principal units of exchange. Therefore, we conclude that sHSP complexes are in rapid dissociation/reassociation equilibria with suboligomeric forms. More generally, these experiments illustrate a powerful approach for the real-time analysis of the evolution of transient species and their relative populations during the subunit exchange of multimeric protein complexes.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available