tailieunhanh - Báo cáo khoa học: Temperature and concentration-controlled dynamics of rhizobial small heat shock proteins

A hallmark ofa-crystallin-type small heat shock proteins (sHsps) is their highly dynamic oligomeric structure which promotes intermolecular interactions involved in subunit exchange and substrate binding (chaperone-like activity). We studied the oligomeric features of two classes of bacterial sHsps by size exclusion chromatography and nanoelectro-spray mass of both classes formed large complexes that rapidly dissociated upon dilution and at physiologically relevant heat shock temperatures | Eur. J. Biochem. 271 2494-2503 2004 FEBS 2004 doi Temperature and concentration-controlled dynamics of rhizobial small heat shock proteins Nicolas Lentze1 J. Andrew Aquilina2 Mareike Lindbauer1 Carol V. Robinson2 and Franz Narberhaus1 3 1Institut fur Mikrobiologie Eidgenossische Technische Hochschule Zurich Switzerland department of Chemistry Cambridge University Cambridge UK and 3Lehrstuhl fur Biologie der Mikroorganismen Ruhr-Universitdt Bochum Bochum Germany A hallmark of a-crystallin-type small heat shock proteins sHsps is their highly dynamic oligomeric structure which promotes intermolecular interactions involved in subunit exchange and substrate binding chaperone-like activity . We studied the oligomeric features of two classes of bacterial sHsps by size exclusion chromatography and nanoelectrospray mass spectrometry. Proteins of both classes fomied large complexes that rapidly dissociated upon dilution and at physiologically relevant heat shock temperatures. As the secondary structure was not perturbed temperature- and concentration-dependent dissociations were fully reversible. Complexes formed between sHsps and the model substrate citrate synthase were stable and exceeded the size of sHsp oligomers. Small Hsp . mutated m a nigE 00101 11x1 gỌy-cine residue at the C-terminal end of the a-crystallin domain formed labile complexes that disassembled more readily than the corresponding wild-type proteins. Redueed tom-plex stability coincided with reduced chaperone activity. Keywords a-crystallin chaperone oligomerization sHsp small heat shock protein. Small heat shock proteins sHsps or a-Hsps form a distinct family of molecular chaperones. They are found m mott organisms and are typically induced upon stress 1-3 . Most sHsps tested to date prevent thermal- or chemical-induced aggregation of a variety of model substrates in vitro by binding to unfolding intermediates. The reoulting sHsp substrate complexes are very large and .