2h50

Publication Abstract from PubMed

Small heat shock proteins are a superfamily of molecular chaperones that suppress protein aggregation and provide protection from cell stress. A key issue for understanding their action is to define the interactions of subunit domains in these oligomeric assemblies. Cryo-electron microscopy of yeast Hsp26 reveals two distinct forms, each comprising 24 subunits arranged in a porous shell with tetrahedral symmetry. The subunits form elongated, asymmetric dimers that assemble via trimeric contacts. Modifications of both termini cause rearrangements that yield a further four assemblies. Each subunit contains an N-terminal region, a globular middle domain, the alpha-crystallin domain, and a C-terminal tail. Twelve of the C termini form 3-fold assembly contacts which are inserted into the interior of the shell, while the other 12 C termini form contacts on the surface. Hinge points between the domains allow a variety of assembly contacts, providing the flexibility required for formation of supercomplexes with non-native proteins.

Multiple distinct assemblies reveal conformational flexibility in the small heat shock protein Hsp26.,White HE, Orlova EV, Chen S, Wang L, Ignatiou A, Gowen B, Stromer T, Franzmann TM, Haslbeck M, Buchner J, Saibil HR Structure. 2006 Jul;14(7):1197-204. PMID:16843901^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.