PDBsum entry: 1g31

Chaperone

PDB id: 1g31

Contents

Protein chains

(+ 1 more) 107 a.a. *

Ligands

PO4 ×19

Metals

__K ×11

Waters ×469

* Residue conservation analysis

PDB id:

1g31

Name:

Chaperone

Title:

Gp31 co-chaperonin from bacteriophage t4

Structure:

Gp31. Chain: a, b, c, d, e, f, g. Engineered: yes

Source:

Enterobacteria phage t4. Organism_taxid: 10665. Organ: brain. Cellular_location: cytoplasm. Gene: 31. Expressed in: escherichia coli. Expression_system_taxid: 562.

Biol. unit:

Heptamer (from PDB file)

Resolution:

2.30Å R-factor: 0.225 R-free: 0.254

Authors:

J.F.Hunt,S.M.Van Der Vies,L.Henry,J.Deisenhofer

Key ref:

J.F.Hunt et al. (1997). Structural adaptations in the specialized bacteriophage T4 co-chaperonin Gp31 expand the size of the Anfinsen cage. Cell, 90, 361-371. PubMed id: 9244309 DOI: 10.1016/S0092-8674(00)80343-8

Date:

27-Mar-98 Release date: 26-Aug-98

Protein chains

P17313  (VG31_BPT4) -  Capsid assembly protein Gp31

Seq: 111 a.a.

Struc: 107 a.a.

 Gene Ontology (GO) functional annotation 

• Cellular component: cytoplasm (1 term)
• Biological process: viral capsid assembly (2 terms)

DOI no: 10.1016/S0092-8674(00)80343-8

Cell 90:361-371 (1997)

PubMed id: 9244309

Structural adaptations in the specialized bacteriophage T4 co-chaperonin Gp31 expand the size of the Anfinsen cage.

J.F.Hunt, S.M.van der Vies, L.Henry, J.Deisenhofer.

ABSTRACT

The Gp31 protein from bacteriophage T4 functionally substitutes for the bacterial co-chaperonin GroES in assisted protein folding reactions both in vitro and in vivo. But Gp31 is required for the folding and/or assembly of the T4 major capsid protein Gp23, and this requirement cannot be satisfied by GroES. The 2.3 A crystal structure of Gp31 shows that its tertiary and quaternary structures are similar to those of GroES despite the existence of only 14% sequence identity between the two proteins. However, Gp31 shows a series of structural adaptations which will increase the size and the hydrophilicity of the "Anfinsen cage," the enclosed cavity within the GroEL/GroES complex that is the location of the chaperonin-assisted protein folding reaction.

Selected figure(s)

Figure 1.
Figure 1. Electron Density Maps(A) Electron density map ([29]) obtained by iterative solvent flattening (without NCS averaging) starting with the initial molecular replacement phases. The backbone trace of the molecular replacement search model is shown in yellow. There is a single Gp31 heptamer in the crystallographic asymmetric unit.(B) The SIGMA-A ([49]) weighted (2F[o]-F[c]) map from the refined model. The phosphate zipper holding together the mobile loop cage is shown in a view looking down the 7-fold symmetry axis. The crystallographic 2-fold axis runs parallel to the plane of the page. The electron density for the phosphate anions is highlighted in red.

Figure 2.
Figure 2. The Structure of Gp31(A) Crystallographically observed secondary structure in Gp31 and structural alignment of Gp31 with GroES. Red indicates β-strands, blue indicates α-helices, and green indicates 3[10]-helices. The Greek letters indicate β-turn classification ([66]). The shaded boxes delineate the 58 residues of the shared structural core in Gp31 and GroES. The underlined sequences represent the dynamically disordered residues of the mobile loop as observed by NMR ( [36 and 37]). The residues in Gp31 making van der Waals contacts in the hydrophobic core of the β-barrel are indicated by asterisks, and the location of the turn in the GroEL-bound conformation of the mobile loop is indicated by “t” ( [37]). Vertical boxes indicate positions where identical residues occur in the β-barrel domain of quinoneoxidoreductase which shares the same fold as Gp31/GroES ([44]). The numbers at the bottom refer to the sequence of Gp31.(B) Stereo pair ([34 and 43]) showing the Cα trace of the Gp31 and GroES monomers after least-squares alignment of the structural core. Gp31 is shown in light green, except for the mobile loop which is shown in yellow, and GroES is shown in dark purple. The side-chain of Gln75 is shown for Gp31, while the side-chain of Tyr71 is shown for GroES.(C) Two orthogonal views of the Gp31 and GroES heptamers (with color coding as in [B]); the single well-ordered copy of the mobile loop observed in the crystal structure GroES heptamer is also shown in yellow.

The above figures are reprinted by permission from Cell Press: Cell (1997, 90, 361-371) copyright 1997.

Figures were selected by an automated process.