PDBsum entry: 3bvo

Chaperone

PDB id: 3bvo

Contents

Protein chains

197 a.a. *

177 a.a. *

Ligands

SO4

Metals

_ZN ×2

* Residue conservation analysis

PDB id:

3bvo

Name:

Chaperone

Title:

Crystal structure of human co-chaperone protein hscb

Structure:

Co-chaperone protein hscb, mitochondrial precurso chain: a, b. Fragment: residues 30-235. Synonym: hsc20, dnaj homolog subfamily c member 20. Engineered: yes

Source:

Homo sapiens. Human. Organism_taxid: 9606. Gene: hscb, dnajc20, hsc20. Expressed in: escherichia coli. Expression_system_taxid: 562.

Resolution:

3.00Å R-factor: 0.240 R-free: 0.288

Authors:

E.Bitto,C.A.Bingman,J.G.Mccoy,G.E.Wesenberg,G.N.Phillips Jr. For Eukaryotic Structural Genomics (Cesg)

Key ref:

E.Bitto et al. (2008). Structure of human J-type co-chaperone HscB reveals a tetracysteine metal-binding domain. J Biol Chem, 283, 30184-30192. PubMed id: 18713742 DOI: 10.1074/jbc.M804746200

Date:

07-Jan-08 Release date: 15-Jan-08

Protein chain

Q8IWL3  (HSC20_HUMAN) -  Iron-sulfur cluster co-chaperone protein HscB, mitochondrial

Seq: 235 a.a.

Struc: 197 a.a.

Protein chain

Q8IWL3  (HSC20_HUMAN) -  Iron-sulfur cluster co-chaperone protein HscB, mitochondrial

Seq: 235 a.a.

Struc: 177 a.a.

 Gene Ontology (GO) functional annotation 

• Biological process: protein folding (1 term)
• Biochemical function: heat shock protein binding (2 terms)

DOI no: 10.1074/jbc.M804746200

J Biol Chem 283:30184-30192 (2008)

PubMed id: 18713742

Structure of human J-type co-chaperone HscB reveals a tetracysteine metal-binding domain.

E.Bitto, C.A.Bingman, L.Bittova, D.A.Kondrashov, R.M.Bannen, B.G.Fox, J.L.Markley, G.N.Phillips.

ABSTRACT

Iron-sulfur proteins play indispensable roles in a broad range of biochemical processes. The biogenesis of iron-sulfur proteins is a complex process that has become a subject of extensive research. The final step of iron-sulfur protein assembly involves transfer of an iron-sulfur cluster from a cluster-donor to a cluster-acceptor protein. This process is facilitated by a specialized chaperone system, which consists of a molecular chaperone from the Hsc70 family and a co-chaperone of the J-domain family. The 3.0 A crystal structure of a human mitochondrial J-type co-chaperone HscB revealed an L-shaped protein that resembles Escherichia coli HscB. The important difference between the two homologs is the presence of an auxiliary metal-binding domain at the N terminus of human HscB that coordinates a metal via the tetracysteine consensus motif CWXCX(9-13)FCXXCXXXQ. The domain is found in HscB homologs from animals and plants as well as in magnetotactic bacteria. The metal-binding site of the domain is structurally similar to that of rubredoxin and several zinc finger proteins containing rubredoxin-like knuckles. The normal mode analysis of HscB revealed that this L-shaped protein preferentially undergoes a scissors-like motion that correlates well with the conformational changes of human HscB observed in the crystals.

Selected figure(s)

Figure 3.
Structural homologs of the N-domain. A stereo diagram depicts Cα traces of structurally superposed hHscB (blue), zinc-substituted rubredoxin from C. pasteurianum (66) (Protein Data Bank code 1irn, red), and NZF domain of Npl4(59) (Protein Data Bank code 1nj3, cyan). Four cysteine residues located in the apposed rubredoxin knuckles provide coordination for a metal ion (red sphere).

Figure 4.
Observed and theoretical conformational variability of hHscB. a, stereodiagram of Cα traces of chain A (red) and chain B (cyan) of hHscB as observed in the crystal lattice. The N- and J-domains of the both chains were structurally superposed to reveal conformational differences in the arrangement of C-domains. The black arrow points to the topologically equivalent residues at the tip of the C-domain that were displaced by ∼10 Å. The red sphere represents a metal ion coordinated by the N-domain. b, the colored rods represent a direction (white to red) and amplitude of motion of the hHscB Cα-atoms along the three lowest frequency nontrivial normal modes (left to right). All of the modes are also depicted using simplifying schematic drawings. The first lowest frequency nontrivial normal mode (left) can be understood as scissors-like opening and closure of the molecule of hHscB. The second lowest frequency nontrivial normal mode (middle) reveals a rotational motion of the N- and J-domains and sideways twisting motion of the C-domain. Finally, the third lowest frequency nontrivial normal mode (right) reveals the rotational motion of the C-domain and sideways twisting motion of the N- and J-domains.

The above figures are reprinted from an Open Access publication published by the ASBMB: J Biol Chem (2008, 283, 30184-30192) copyright 2008.

Figures were selected by an automated process.