PDBsum entry 1im2

Chaperone

PDB id: 1im2

Contents

Protein chain

346 a.a. *

Ligands

SO4

ADP

* Residue conservation analysis

PDB id:

1im2

Name:

Chaperone

Title:

Hslu, haemophilus influenzae, selenomethionine variant

Structure:

Atp-dependent hsl protease atp-binding subunit hslu. Chain: a. Synonym: heat shock protein hslu. Engineered: yes

Source:

Haemophilus influenzae. Organism_taxid: 727. Expressed in: escherichia coli. Expression_system_taxid: 562.

Biol. unit:

Hexamer (from PDB file)

Resolution:

2.80Å R-factor: 0.233 R-free: 0.250

Authors:

C.B.Trame,D.B.Mckay

Key ref:

C.B.Trame and D.B.McKay (2001). Structure of Haemophilus influenzae HslU protein in crystals with one-dimensional disorder twinning. Acta Crystallogr D Biol Crystallogr, 57, 1079-1090. PubMed id: 11468391 DOI: 10.1107/S0907444901007673

Date:

09-May-01 Release date: 08-Aug-01

Protein chain

P43773  (HSLU_HAEIN) -  ATP-dependent protease ATPase subunit HslU from Haemophilus influenzae (strain ATCC 51907 / DSM 11121 / KW20 / Rd)

Seq: 444 a.a.

Struc: 346 a.a.

DOI no: 10.1107/S0907444901007673

Acta Crystallogr D Biol Crystallogr 57:1079-1090 (2001)

PubMed id: 11468391

Structure of Haemophilus influenzae HslU protein in crystals with one-dimensional disorder twinning.

C.B.Trame, D.B.McKay.

ABSTRACT

The structure of the Haemophilus influenzae HslU protein, a molecular chaperone of the Clp/Hsp100 family, has been solved to 2.3 A by molecular replacement using a model of the homologous Escherichia coli protein. The crystals in which the structure was solved have an unusual twinning, or one-dimensional disorder, in which each successive crystal-packing layer is displaced laterally relative to the one below it. A model for the twinning and an algorithm for detwinning the data are described. It is known from other work that when the HslU hexamer binds its cognate protease HslV, the carboxy-terminal helices of HslU protomers distend and bind between HslV subunits. Comparison of HslU alone with its structure in the HslUV complex reveals several conserved amino-acid residues whose side-chain interactions differ between the two structures, suggesting that they may be part of a conformational switch that facilitates the release of the HslU carboxy-terminal helices when HslV binds.

Selected figure(s)

Figure 5.
Figure 5 Representative electron-density map around the nucleotide-binding site. Stereoview of a simulated-annealing omit map (green, contoured at 4.2 ) in which ADP and Arg394 were omitted from the model used in refinement. Protein is shown as a ribbon diagram; ADP and residues Arg394 and Lys63 are shown in ball-and-stick representation. Distances from the non-bonded guanidinium N atoms of Arg394 to the nearest phosphate O atom are 2.8 and 2.5 Å; distance from the amino group of Lys63 to the nearest phosphate O atom is 2.8 Å.

Figure 9.
Figure 9 Electrostatic surface potentials of HslV and HslU. Positions of some amino-acid residues are labeled in each figure. (a) View looking down the sixfold axis of the HslV dodecamer from the HslUV complex (Sousa et al., 2000[Sousa, M. C., Trame, C. B., Tsuruta, H., Wilbanks, S. M., Reddy, V. S. & McKay, D. B. (2000). Cell, 103, 633-643.]). Arrows indicate the electropositive grooves into which the carboxy-terminal helices of HslU intercalate. (b) Carboxy-terminal helix of one protomer of HslU in its conformation from the HslUV complex. (c) Side view showing the interface between the carboxy-terminal helix of HslU, shown as a ball-and-stick model, and the groove between two HslV protomers. Electrostatic potentials were computed with the program GRASP (Nicholls & Honig, 1991[Nicholls, A. & Honig, B. J. (1991). J. Comput. Chem. 12, 435-445.]), using a dielectric constant of 2.0 for the interior of the protein and 80.0 for the solvent area and an effective ionic strength equivalent to 1.0 M salt.

The above figures are reprinted by permission from the IUCr: Acta Crystallogr D Biol Crystallogr (2001, 57, 1079-1090) copyright 2001.

Figures were selected by an automated process.