sHsps in big packages – sHSP native structure
Although sHSP/αC monomers are relatively small, the majority of these proteins exist as oligomers of between 12 to >48 subunits in their native state. The first solved structures of sHSP/αC oligomers were those of the 24-subunit Hsp16.5 from the archaeon Methanocaldococcus jannaschii, (formerly classified within the genus Methanococcus) and the eukaryotic dodecameric Hsp16.9 from Triticum aestivum (wheat), published by our group in collaboration with CHristine SLingsby (Birkebeck College, UK). These structures defined the architecture of the ACD, identified a dimeric substructure, and clarified the contacts required for oligomerization. Recently, additional structures of primarily the ACD have been determined from bacteria and metazoans, including human HspB5. Obtaining high resolution data for oligomeric forms of the metazoan proteins has been challenging because of the well-documented polydispersity of the oligomers.