PDBsum entry 1e8q

Cellulose docking domain

PDB id: 1e8q

Contents

Protein chain

46 a.a. *

* Residue conservation analysis

PDB id:

1e8q

Name:

Cellulose docking domain

Title:

Characterisation of the cellulose docking domain from piromyces equi

Structure:

Endoglucanase 45a. Chain: a. Fragment: cellulose docking domain. Synonym: dockerin. Engineered: yes

Source:

Piromyces equi. Organism_taxid: 99929. Gene: cel45a. Expressed in: escherichia coli. Expression_system_taxid: 562.

NMR struc:

5 models

Authors:

S.Raghothama,R.Y.Eberhardt,P.White,G.P.Hazlewood,H.J.Gilbert, P.J.Simpson,M.P.Williamson

Key ref:

S.Raghothama et al. (2001). Characterization of a cellulosome dockerin domain from the anaerobic fungus Piromyces equi. Nat Struct Biol, 8, 775-778. PubMed id: 11524680 DOI: 10.1038/nsb0901-775

Date:

28-Sep-00 Release date: 07-Sep-01

Protein chain

Q9P868  (Q9P868_PIREQ) -  Cellulase from Piromyces equi

Seq: 410 a.a.

Struc: 46 a.a.*

* PDB and UniProt seqs differ at 1 residue position (black cross)

Enzyme reactions

• Enzyme class: E.C.3.2.1.4 - cellulase.
• Reaction: Endohydrolysis of 1,4-beta-D-glucosidic linkages in cellulose, lichenin and cereal beta-D-glucans.

DOI no: 10.1038/nsb0901-775

Nat Struct Biol 8:775-778 (2001)

PubMed id: 11524680

Characterization of a cellulosome dockerin domain from the anaerobic fungus Piromyces equi.

S.Raghothama, R.Y.Eberhardt, P.Simpson, D.Wigelsworth, P.White, G.P.Hazlewood, T.Nagy, H.J.Gilbert, M.P.Williamson.

ABSTRACT

The recycling of photosynthetically fixed carbon in plant cell walls is a key microbial process. In anaerobes, the degradation is carried out by a high molecular weight multifunctional complex termed the cellulosome. This consists of a number of independent enzyme components, each of which contains a conserved dockerin domain, which functions to bind the enzyme to a cohesin domain within the protein scaffoldin protein. Here we describe the first three-dimensional structure of a fungal dockerin, the N-terminal dockerin of Cel45A from the anaerobic fungus Piromyces equi. The structure contains a novel fold of 42 residues. The ligand binding site consists of residues Trp 35, Tyr 8 and Asp 23, which are conserved in all fungal dockerins. The binding site is on the opposite side of the N- and C-termini of the molecule, implying that tandem dockerin domains, seen in the majority of anaerobic fungal plant cell wall degrading enzymes, could present multiple simultaneous binding sites and, therefore, permit tailoring of binding to catalytic demands.

Selected figure(s)

Figure 2.
Figure 2. Solution structure of the P. equi dockerin. a, Stereo view of the ensemble of 34 structures, colored from red at the N-terminus to blue at the C-terminus. b, Stereo MOLSCRIPT27 diagram of the dockerin structure, showing the locations of disulfide bridges and the binding site residues discussed in the text. The protein present in the sample consisted of 52 residues -- that is, the 38-residue 'core' sequence that is highly conserved in fungal dockerins, plus all 12 residues C-terminal of the core sequence prior to the start of the second dockerin domain, and two N-terminal residues from the GST-tag. The figure shows only the ordered residues -2 -44. c, Surface of the protein, in the same orientation as (b). Side chains of residues Tyr 8 and Trp 35 are in purple, and Asp 23 in light lilac. Acidic residues are in red, basic in dark blue and hydrophobic in yellow.

Figure 3.
Figure 3. 15N T[2] values for backbone nitrogens. Values (ms) are plotted against residue number.

The above figures are reprinted by permission from Macmillan Publishers Ltd: Nat Struct Biol (2001, 8, 775-778) copyright 2001.

Figures were selected by an automated process.