Topology and dynamics of the 10 kDa C-terminal domain of DnaK in solution.
Hsp70 molecular chaperones contain three distinct structural domains, a 44 kDa N-terminal ATPase domain, a 17 kDa peptide-binding domain, and a 10 kDa C-terminal domain. The ATPase and peptide binding domains are conserved in sequence and are functionally well characterized. The function of the 10 kDa variable C-terminal domain is less well understood. We have characterized the secondary structure and dynamics of the C-terminal domain from the Escherichia coli Hsp70, DnaK, in solution by high-resolution NMR. The domain was shown to be comprised of a rigid structure consisting of four helices and a flexible C-terminal subdomain of approximately 33 amino acids. The mobility of the flexible region is maintained in the context of the full-length protein and does not appear to be modulated by the nucleotide state. The flexibility of this region appears to be a conserved feature of Hsp70 architecture and may have important functional implications. We also developed a method to analyze 15N nuclear spin relaxation data, which allows us to extract amide bond vector directions relative to a unique diffusion axis. The extracted angles and rotational correlation times indicate that the helices form an elongated, bundle-like structure in solution.
Institute of Molecular Biology, University of Oregon, Eugene 97403, USA.
E B
EB
Bertelsen
H
H
Zhou
D F
DF
Lowry
G C
GC
Flynn
F W
FW
Dahlquist
D000595:Amino Acid Sequence; D004926:Escherichia coli / Q000737:chemistry; D029968:Escherichia coli Proteins; D018840:HSP70 Heat-Shock Proteins / Q000032:analysis*; D009682:Magnetic Resonance Spectroscopy; D008969:Molecular Sequence Data; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary
D029968:Escherichia coli Proteins; D018840:HSP70 Heat-Shock Proteins; C063842:dnaK protein, E coli