Enhanced molecular chaperone activity of the small heat-shock protein alphaB-cystallin following covalent immobilization onto a solid-phase support

Biopolymers. 2011 Jun;95(6):376-89. doi: 10.1002/bip.21584.

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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amyloid / antagonists & inhibitors
  • Amyloid / chemistry
  • Caseins / analysis
  • Heat-Shock Proteins, Small / chemistry*
  • Immobilized Proteins / chemistry*
  • Macroglobulins / analysis
  • Microscopy, Atomic Force
  • Molecular Chaperones / chemistry*
  • Photoelectron Spectroscopy
  • Protein Binding
  • Protein Folding
  • Quartz Crystal Microbalance Techniques
  • Solutions
  • Surface Properties
  • alpha-Crystallin B Chain / chemistry*

Substances

  • Amyloid
  • Caseins
  • Heat-Shock Proteins, Small
  • Immobilized Proteins
  • Macroglobulins
  • Molecular Chaperones
  • Solutions
  • alpha-Crystallin B Chain