PDBsum entry 1gml

Chaperone

PDB id: 1gml

Contents

Protein chains

155 a.a. *

Ligands

GOL ×4

Waters ×645

* Residue conservation analysis

PDB id:

1gml

Name:

Chaperone

Title:

Crystal structure of the mouse cct gamma apical domain (triclinic)

Structure:

T-complex protein 1 subunit gamma. Chain: a, b, c, d. Fragment: apical domain, residues 210-380. Synonym: tcp-1-gamma, cct-gamma, matricin, mtric-p5. Engineered: yes

Source:

Mus musculus. Mouse. Organism_taxid: 10090. Expressed in: escherichia coli. Expression_system_taxid: 562.

Biol. unit:

Dimer (from PDB file)

Resolution:

2.20Å R-factor: 0.203 R-free: 0.234

Authors:

G.Pappenberger,J.A.Wilsher,S.M.Roe,K.R.Willison,L.H.Pearl

Key ref:

G.Pappenberger et al. (2002). Crystal structure of the CCTgamma apical domain: implications for substrate binding to the eukaryotic cytosolic chaperonin. J Mol Biol, 318, 1367-1379. PubMed id: 12083524 DOI: 10.1016/S0022-2836(02)00190-0

Date:

17-Sep-01 Release date: 18-Jun-02

Protein chains

P80318  (TCPG_MOUSE) -  T-complex protein 1 subunit gamma from Mus musculus

Seq: 545 a.a.

Struc: 155 a.a.

DOI no: 10.1016/S0022-2836(02)00190-0

J Mol Biol 318:1367-1379 (2002)

PubMed id: 12083524

Crystal structure of the CCTgamma apical domain: implications for substrate binding to the eukaryotic cytosolic chaperonin.

G.Pappenberger, J.A.Wilsher, S.M.Roe, D.J.Counsell, K.R.Willison, L.H.Pearl.

ABSTRACT

The chaperonin containing TCP-1 (CCT, also known as TRiC) is the only member of the chaperonin family found in the cytosol of eukaryotes. Like other chaperonins, it assists the folding of newly synthesised proteins. It is, however, unique in its specificity towards only a small subset of non-native proteins. We determined two crystal structures of mouse CCTgamma apical domain at 2.2 A and 2.8 A resolution. They reveal a surface patch facing the inside of the torus that is highly evolutionarily conserved and specific for the CCTgamma apical domain. This putative substrate-binding region consists of predominantly positively charged side-chains. It suggests that the specificity of this apical domain towards its substrate, partially folded tubulin, is conferred by polar and electrostatic interactions. The site and nature of substrate interaction are thus profoundly different between CCT and its eubacterial homologue GroEL, consistent with their different functions in general versus specific protein folding assistance.

Selected figure(s)

Figure 2.
Figure 2. Structural comparison of apical domains from group II and group I chaperonins. (a) Stereo view of a ribbon diagram of the CCTg apical domain structure. The secondary structure elements are numbered according to Braig et al.[46] a-Helices, H8-H10; b-strands, S6-S13. No interpretable electron density was observed for the N-terminal half of the helical protrusion (K248-D263). (b) b-Apical domain of the archaeal group II chaperonin thermosome. Coordinates were obtained from the crystal structure of the complete thermosome. [6] (c) Apical domain of the eubacterial group I chaperonin GroEL. [29] (d) Stereo view of the 2F[o] -F[c] electron density map from the triclinic crystal form, contoured at 1.0s. The cysteine residues C366 and C372 are found to form a disulphide bridge (indicated), covalently closing the loop around P369 near the C terminus of the domain.

Figure 3.
Figure 3. Identification of the substrate-binding region of the mouse CCTg apical domain. In the left column, the protein regions lining the inside of the torus are facing the viewer. The orientation in the right column is rotated by 180°, showing the outside of the torus. (a) Ribbon diagram to illustrate the orientations of the molecule. (b) Surface regions interacting with neighbouring subunits (green, blue) or the intermediate domain of the same subunit (red) in the complete CCT complex. This has been modelled on the basis of the thermosome crystal structure[6] by superimposing the CCTg apical domain onto the thermosome b-apical domain and labelling all atoms of the CCTg apical domain closer than 5 Å to atoms of the surrounding thermosome structure. (c) Residue conservation, mapped onto the surface of the molecule (blue, conserved; red, variable). (d) Signature residues of the CCTg apical domain (green), mapped onto its surface.

The above figures are reprinted by permission from Elsevier: J Mol Biol (2002, 318, 1367-1379) copyright 2002.

Figures were selected by an automated process.