Abstract
Self-association of ClpB (a mixture of 95- and 80-kDa subunits) has been studied with gel filtration chromatography, analytical ultracentrifugation, and electron microscopy. Monomeric ClpB predominates at low protein concentration (0.07 mg/mL), while an oligomeric form is highly populated at >4 mg/mL. The oligomer formation is enhanced in the presence of 2 mM ATP or adenosine 5'-O-thiotriphosphate (ATPγS). In contrast, 2 mM ADP inhibits full oligomerization of ClpB. The apparent size of the ATP- or ATPγS-induced oligomer, as determined by gel filtration, sedimentation velocity and electron microscopy image averaging, and the molecular weight, as determined by sedimentation equilibrium, are consistent with those of a ClpB hexamer. These results indicate that the oligomerization reactions of ClpB are similar to those of other Hsp100 proteins.
Original language | English |
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Pages (from-to) | 1899-1903 |
Number of pages | 5 |
Journal | Protein Science |
Volume | 8 |
Issue number | 9 |
DOIs | |
State | Published - 1999 |
Externally published | Yes |
Keywords
- Electron microscopy
- Heat-shock proteins
- Nucleotide binding
- Protein association
- Sedimentation equilibrium
- Sedimentation velocity