Related Experiment Videos
The DnaK chaperone system facilitates 30S ribosomal subunit assembly
Jennifer A Maki1, Daniel J Schnobrich, Gloria M Culver
1Department of Biochemistry, Biophysics, and Molecular Biology, Iowa State University, Ames 50011, USA.
Molecular Cell
|August 2, 2002
Summary
The DnaK/hsp70 chaperone system facilitates the assembly of functional Escherichia coli 30S ribosomal subunits in vitro. This discovery reveals a novel role for chaperones in ribosome biogenesis.
Area of Science:
- Molecular Biology
- Cell Biology
- Biochemistry
Background:
- Functional 30S ribosomal subunits of Escherichia coli can be reconstituted in vitro, but with slow kinetics and high temperature dependence.
- These limitations suggest the involvement of additional assembly factors in vivo.
Purpose of the Study:
- To investigate the role of chaperone proteins in the in vitro reconstitution of functional 30S ribosomal subunits.
- To explore the potential involvement of the DnaK/hsp70 chaperone system in ribosome biogenesis.
Main Methods:
- Reconstitution of functional 30S ribosomal subunits in vitro.
- Analysis of the association of DnaK/hsp70 chaperone components with pre-30S particles.
- Assessing the effect of purified DnaK, DnaJ, GrpE, and ATP on subunit assembly.
Main Results:
- Activation of in vitro assembly led to the association of DnaK/hsp70 chaperone components with pre-30S particles.
- Purified DnaK, its cochaperones DnaJ and GrpE, and ATP facilitated the reconstitution of functional 30S subunits under nonpermissive conditions.
- A link was observed between DnaK, 30S subunit components, and ribosome biogenesis both in vivo and in vitro.
Conclusions:
- The DnaK/hsp70 chaperone system plays a novel role in facilitating 30S ribosomal subunit assembly.
- This finding expands the known functions of the DnaK/hsp70 system beyond protein folding.
- Chaperone-assisted assembly provides a mechanism for efficient ribosome biogenesis.