Solution conformation of wild-type E. coli Hsp70 (DnaK) chaperone complexed with ADP and substrate

Area of Science:

• Molecular biology
• Structural biology
• Biochemistry

Background:

• DnaK is a key Hsp70 molecular chaperone in E. coli.
• It consists of a nucleotide-binding domain (NBD) and a substrate-binding domain (SBD).

Purpose of the Study:

• To determine the experimental structure of full-length DnaK complexed with a peptide and ADP.
• To investigate the dynamic relationship between the NBD and SBD.

Main Methods:

• NMR residual dipolar coupling
• Spin labeling
• Analysis of existing crystal structures for isolated domains

Main Results:

• An average structure of full-length DnaK was determined in aqueous solution.
• The NBD and SBD exhibit loose linkage, moving within +/-35 degrees.
• The linker region is a dynamic random coil.
• The SBD is positioned near NBD subdomain IA, suggesting allosteric communication.

Conclusions:

• The dynamic interaction between DnaK's domains is essential for its function.
• The determined structure provides insights into Hsp70 chaperone allosteric mechanisms.