title: Enhanced molecular chaperone activity of the small heat-shock protein alphaB-cystallin following covalent immobilization onto a solid-phase support.
abstract: The well-characterized small heat-shock protein, alphaB-crystallin, acts as a molecular chaperone by interacting with unfolding proteins to prevent their aggregation and precipitation. Structural perturbation (e.g., partial unfolding) enhances the in vitro chaperone activity of alphaB-crystallin. Proteins often undergo structural perturbations at the surface of a synthetic material, which may alter their biological activity. This study investigated the activity of alphaB-crystallin when covalently bound to a support surface; alphaB-crystallin was immobilized onto a range of solid material surfaces, and its characteristics and chaperone activity were assessed. Immobilization was achieved via a plasma-deposited thin polymeric interlayer containing aldehyde surface groups and reductive amination, leading to the covalent binding of alphaB-crystallin lysine residues to the surface aldehyde groups via Schiff-base linkages. Immobilized alphaB-crystallin was characterized by X-ray photoelectron spectroscopy, atomic force microscopy, and quartz crystal microgravimetry, which showed that  300 ng cm(-2) (dry mass) of oligomeric alphaB-crystallin was bound to the surface. Immobilized alphaB-crystallin exhibited a significant enhancement (up to 5000-fold, when compared with the equivalent activity of alphaB-crystallin in solution) of its chaperone activity against various proteins undergoing both amorphous and amyloid fibril forms of aggregation. The enhanced molecular chaperone activity of immobilized alphaB-crystallin has potential applications in preventing protein misfolding, including against amyloid disease processes, such as dialysis-related amyloidosis, and for biodiagnostic detection of misfolded proteins.
authors.affiliation: School of Chemistry and Physics, The University ofAdelaide, Adelaide, South Australia 5005, Australia.
authors.forename: Megan
authors.initials: M
authors.lastname: Garvey
authors.forename: Stefani S
authors.initials: SS
authors.lastname: Griesser
authors.forename: Hans J
authors.initials: HJ
authors.lastname: Griesser
authors.forename: Benjamin
authors.initials: B
authors.lastname: Thierry
authors.forename: Matthew R
authors.initials: MR
authors.lastname: Nussio
authors.forename: Joseph G
authors.initials: JG
authors.lastname: Shapter
authors.forename: Heath
authors.initials: H
authors.lastname: Ecroyd
authors.forename: Sofia
authors.initials: S
authors.lastname: Giorgetti
authors.forename: Vittorio
authors.initials: V
authors.lastname: Bellotti
authors.forename: Juliet A
authors.initials: JA
authors.lastname: Gerrard
authors.forename: John A
authors.initials: JA
authors.lastname: Carver
mesh_terms: D000682:Amyloid / Q000037:antagonists & inhibitors / Q000737:chemistry; D002364:Caseins / Q000032:analysis; D050888:Heat-Shock Proteins, Small / Q000737:chemistry*; D055767:Immobilized Proteins / Q000737:chemistry*; D008259:Macroglobulins / Q000032:analysis; D018625:Microscopy, Atomic Force; D018832:Molecular Chaperones / Q000737:chemistry*; D056951:Photoelectron Spectroscopy; D011485:Protein Binding; D017510:Protein Folding; D058525:Quartz Crystal Microbalance Techniques; D012996:Solutions; D013499:Surface Properties; D038203:alpha-Crystallin B Chain / Q000737:chemistry*
chemical_list: D000682:Amyloid; D002364:Caseins; D050888:Heat-Shock Proteins, Small; D055767:Immobilized Proteins; D008259:Macroglobulins; D018832:Molecular Chaperones; D012996:Solutions; D038203:alpha-Crystallin B Chain