The small heat-shock proteins HSPB2 and HSPB3 form well-defined heterooligomers in a unique 3 to 1 subunit ratio
| Autor: | Wilbert C. Boelens, John den Engelsman, Wilma Vree Egberts, Bram Kamps, Patricia Y. W. Dankers, Carol V. Robinson, Csaba Böde, Sandor Boros, J. Andrew Aquilina, Laura A. Lane, Justin L. P. Benesch, Wilfried W. de Jong |
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| Přispěvatelé: | Macro-Organic Chemistry |
| Rok vydání: | 2009 |
| Předmět: |
Spectrometry
Mass Electrospray Ionization Circular dichroism Hot Temperature Surface Properties Protein subunit Molecular Sequence Data HSP27 Heat-Shock Proteins Membrane transport and intracellular motility [NCMLS 5] Plasma protein binding Oligomer Anilino Naphthalenesulfonates chemistry.chemical_compound Protein structure Structural Biology Heat shock protein Animals Humans Amino Acid Sequence Protein Structure Quaternary Molecular Biology Peptide sequence Heat-Shock Proteins Renal disorder [IGMD 9] Circular Dichroism Bio-Molecular Chemistry Rats Molecular Weight Protein Subunits chemistry Biochemistry Hydrophobic and Hydrophilic Interactions Sequence Alignment Protein Binding |
| Zdroj: | Journal of Biological Chemistry, 393, 5 Journal of Biological Chemistry, 393 Journal of Molecular Biology, 393, 1022-32 Journal of Molecular Biology, 393, 5, pp. 1022-32 Journal of Molecular Biology, 393(5), 1022-1032. Academic Press Inc. |
| ISSN: | 0021-9258 0022-2836 |
| Popis: | Contains fulltext : 81177.pdf (Publisher’s version ) (Closed access) Various mammalian small heat-shock proteins (sHSPs) can interact with one another to form large polydisperse assemblies. In muscle cells, HSPB2/MKBP (myotonic dystrophy protein kinase-binding protein) and HSPB3 have been shown to form an independent complex. To date, the biochemical properties of this complex have not been thoroughly characterized. In this study, we show that recombinant HSPB2 and HSPB3 can be successfully purified from Escherichia coli cells co-expressing both proteins. Nanoelectrospray ionization mass spectrometry and sedimentation velocity analytical ultracentrifugation analysis showed that HSPB2/B3 forms a series of well defined hetero-oligomers, consisting of 4, 8, 12, 16, 20 and 24 subunits, each maintaining a strict 3:1 HSPB2/HSPB3 subunit ratio. These complexes are thermally stable up to 40 degrees C, as determined by far-UV circular dichroism spectroscopy. Surprisingly, HSPB2/B3 exerted a poor chaperone-like and thermoprotective activity, which is likely related to the low surface hydrophobicity, as revealed by its interaction with the hydrophobic probe 1-anilino-8-naphthalenesulfonic acid. Co-immunoprecipitation experiments demonstrated that the HSPB2/B3 oligomer cannot interact with HSP20, HSP27 or alphaB-crystallin, whereas the homomeric form of HSPB2, thus not in complex with HSPB3, could associate efficiently with HSP20. Taken altogether, this study provides evidence that, despite the high level of sequence homology within the sHSP family the biochemical properties of the HSPB2/B3 complex are distinctly different from those of other sHSPs, indicating that the HSPB2/B3 assembly is likely to possess cellular functions other than those of its family members. |
| Databáze: | OpenAIRE |
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