PDBsum entry 2v7y

Chaperone

PDB id

2v7y

Contents

			Protein chain

					504 a.a.

			Ligands

					ADP


					PO4

			Metals

					_MG

			Waters ×166

References listed in PDB file

Key reference

Title

Crystal structures of the 70-Kda heat shock proteins in domain disjoining conformation.

Authors

Y.W.Chang, Y.J.Sun, C.Wang, C.D.Hsiao.

Ref.

J Biol Chem, 2008, 283, 15502-15511. [DOI no: 10.1074/jbc.M708992200]

PubMed id

18400763

Note In the PDB file this reference is annotated as "TO BE PUBLISHED". The citation details given above were identified by an automated search of PubMed on title and author names, giving a perfect match.

Abstract

The 70-kDa heat shock proteins (Hsp70s) are highly conserved ATP-dependent molecular chaperones composed of an N-terminal nucleotide binding domain (NBD) and a C-terminal protein substrate binding domain (SBD) in a bilobate structure. Interdomain communication and nucleotide-dependent structural motions are critical for Hsp70 chaperone functions. Our understanding of these functions remains elusive due to insufficient structural information on intact Hsp70s that represent the different states of the chaperone cycle. We report here the crystal structures of DnaK from Geobacillus kaustophilus HTA426 bound with ADP-Mg(2+)-P(i) at 2.37A and the 70-kDa heat shock cognate protein from Rattus norvegicus bound with ADP-P(i) at 3.5A(.) The NBD and SBD in these structures are significantly separated from each other, and they might depict the ADP-bound conformation. Moreover, a Trp reporter was introduced at the potential interface region between NBD and the interdomain linker of GkDnaK to probe environmental changes. Results from fluorescence measurements support the notion that substrate binding enhances the domain-disjoining behavior of Hsp70 chaperones.



	Figure 1. Overall structure of GkDnaKΔC in the ADP-Mg^2^+-P[i] state and intermolecular interactions between symmetry-related GkDnaKΔC molecules. A, ribbon diagram of the GkDnaKΔC-ADP-Mg^2+-P[i] complex structure and its orthogonal view reveal that the NBD (residues 1-353, blue) and the SBD (residues 365-504, cyan) are connected by an extended linker (residues 354-364, red). The bound nucleotide (ADP, magnesium ion, and P[i]) is represented as spheres. B, the extended hydrophobic linker between the NBD and the SBD of GkDnaKΔC (blue) occupies the substrate binding pocket of a neighboring crystallographic symmetry-related GkDnaKΔC molecule (gold).		Figure 6. Implication of Hsp70 chaperone cycle and benefits for domain-disjoining conformation of Hsp70s. A, schematic representation for the domain rearrangement of Hsp70. The NBD, SBD, and linker of Hsp70 are colored blue, cyan, and gray, respectively. The cochaperones J-domain ATPase activating protein and nucleotide exchange factor are symbolized by letters J and NEF, respectively. The substrate of Hsp70 is represented as red ribbons, and ATP and ADP are as magenta ellipsoids. B, schematic diagram depicting how luminal Hsp70s enlarge their excluded-volume effect by extending the two-lobed conformation (left, before; right, after) while conducting the post-translational translocation of precursor proteins across membranes. The two-lobed structures are Hsp70 molecules in which the NBDs are colored blue, the SBDs are colored cyan, and the interdomain linkers are colored gray. The brown structures represent the channel complexes that span two-layer membranes, and ribbons represent precursor proteins being imported into the lumen. The possible distributing area of the substrate-bound Hsp70 are represented by paler versions of Hsp70 molecules and circled by red dashed lines.

PROCHECK

	Headers