Monitoring the interaction between beta(2)-microglobulin and the molecular chaperone alpha B-crystallin by NMR and mass spectrometry alpha b-crystallin dissociates beta(2)-microglobulin oligomers
Loading...
Date
2013-06-14
Journal Title
Journal ISSN
Volume Title
Publisher
American Society of Biochemistry and Molecular Biology
Abstract
The interaction at neutral pH between wild-type and a variant form (R3A) of the amyloid fibril-forming protein β2-microglobulin (β2m) and the molecular chaperone αB-crystallin was investigated by thioflavin T fluorescence, NMR spectroscopy, and mass spectrometry. Fibril formation of R3Aβ2m was potently prevented by αB-crystallin. αB-crystallin also prevented the unfolding and nonfibrillar aggregation of R3Aβ2m. From analysis of the NMR spectra collected at various R3Aβ2m to αB-crystallin molar subunit ratios, it is concluded that the structured β-sheet core and the apical loops of R3Aβ2m interact in a nonspecific manner with the αB-crystallin. Complementary information was derived from NMR diffusion coefficient measurements of wild-type β2m at a 100-fold concentration excess with respect to αB-crystallin. Mass spectrometry acquired in the native state showed that the onset of wild-type β2m oligomerization was effectively reduced by αB-crystallin. Furthermore, and most importantly, αB-crystallin reversibly dissociated β2m oligomers formed spontaneously in aged samples. These results, coupled with our previous studies, highlight the potent effectiveness of αB-crystallin in preventing β2m aggregation at the various stages of its aggregation pathway. Our findings are highly relevant to the emerging view that molecular chaperone action is intimately involved in the prevention of in vivo amyloid fibril formation. © 2013, The American Society for Biochemistry and Molecular Biology, Inc.
Description
Keywords
Mass spectroscopy, Nuclear magnetic resonance, Proteins, pH value, Fluorescence, NMR spectra
Citation
Esposito, G., Garvey, M., Alverdi, V., Pettirossi, F., Corazza, A., Fogolari, F., Polano, M., Mangione, P. P., Giorgetti, S., Stoppini, M., Rekas, A., Bellotti, V., Heck, A. J. R., & Carver, J. A. (2013). Monitoring the interaction between beta(2)-microglobulin and the molecular chaperone alpha B-crystallin by NMR and mass spectrometry alpha b-crystallin dissociates beta(2)-microglobulin oligomers. Journal of Biological Chemistry, 288(24), 17844-17858. doi:10.1074/jbc.M112.448639