Inter-subunit cross-linking suppressed the dynamic oligomeric dissociation of Mycobacterium tuberculosis Hsp16.3 and reduced its chaperone activity

Biochemistry (Mosc). 2004 May;69(5):552-7. doi: 10.1023/b:biry.0000029854.86015.61.


Small heat shock proteins (sHsps) usually exist as dynamic oligomers and oligomeric dissociation was believed to be a prerequisite for their chaperone activities. The truth of this hypothesis was verified in our present study on Hsp16.3, one member of sHsps from Mycobacterium tuberculosis, mainly by utilizing chemical cross-linking. Analysis using size exclusion chromatography demonstrated that the heat-induced oligomeric dissociation of Hsp16.3 was severely blocked due to highly efficient inter-subunit cross-linkages generated by chemical cross-linking, as well as its chaperone activity being reduced. Further analysis by non-denaturing pore gradient polyacrylamide gel electrophoresis and fluorescence spectrometry revealed that the dynamic oligomeric dissociation/reassociation process of Hsp16.3 at room temperature was suppressed by inter-subunit cross-linkages, accompanied by significantly decreased exposure of hydrophobic surfaces that are usually hidden in oligomers. These findings supported the hypothesis that substrate-binding sites of sHsps are exposed presumably by dissociation of larger oligomers into smaller active oligomers, and therefore such a dissociation process could be adjusted to modulate chaperone activities.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Anilino Naphthalenesulfonates
  • Bacterial Proteins / chemistry
  • Bacterial Proteins / isolation & purification
  • Bacterial Proteins / metabolism*
  • Chaperonins / chemistry
  • Chaperonins / isolation & purification
  • Chaperonins / metabolism*
  • Chromatography, Gel
  • Circular Dichroism
  • Electrophoresis, Gel, Two-Dimensional
  • Mycobacterium tuberculosis / metabolism*
  • Spectrometry, Fluorescence


  • Anilino Naphthalenesulfonates
  • Bacterial Proteins
  • Hsp16.3 protein, Mycobacterium tuberculosis
  • Chaperonins