Structural analysis of substrate binding by the molecular chaperone DnaK.Zhu, X., Zhao, X., Burkholder, W.F., Gragerov, A., Ogata, C.M., Gottesman, M.E., Hendrickson, W.A.
(1996) Science 272: 1606-1614
- PubMed: 8658133
- DOI: https://doi.org/10.1126/science.272.5268.1606
- Primary Citation of Related Structures:
1DKX, 1DKY, 1DKZ
- PubMed Abstract:
DnaK and other members of the 70-kilodalton heat-shock protein (hsp70) family promote protein folding, interaction, and translocation, both constitutively and in response to stress, by binding to unfolded polypeptide segments. These proteins have two functional units: a substrate-binding portion binds the polypeptide, and an adenosine triphosphatase portion facilitates substrate exchange. The crystal structure of a peptide complex with the substrate-binding unit of DnaK has now been determined at 2.0 angstroms resolution. The structure consists of a beta-sandwich subdomain followed by alpha-helical segments. The peptide is bound to DnaK in an extended conformation through a channel defined by loops from the beta sandwich. An alpha-helical domain stabilizes the complex, but does not contact the peptide directly. This domain is rotated in the molecules of a second crystal lattice, which suggests a model of conformation-dependent substrate binding that features a latch mechanism for maintaining long lifetime complexes.
Department of Biochemistry and Molecular Biophysics, College of Physicians and Surgeons, Columbia University, New York 10032, USA.