PDBsum entry: 2j4n

Protein binding

PDB id: 2j4n

Contents

Protein chain

100 a.a. *

* Residue conservation analysis

PDB id:

2j4n

Name:

Protein binding

Title:

Double dockerin from piromyces equi cel45a

Structure:

Endoglucanase 45a. Chain: a. Fragment: first two dockerin domains, residues 21-118. Synonym: cel45a endoglucanase. Engineered: yes

Source:

Piromyces equi. Organism_taxid: 99929. Expressed in: escherichia coli. Expression_system_taxid: 511693.

NMR struc:

6 models

Authors:

T.Nagy,R.B.Tunnicliffe,L.D.Higgins,C.Walters,H.J.Gilbert, M.P.Williamson

Key ref:

T.Nagy et al. (2007). Characterization of a double dockerin from the cellulosome of the anaerobic fungus Piromyces equi. J Mol Biol, 373, 612-622. PubMed id: 17869267 DOI: 10.1016/j.jmb.2007.08.007

Date:

01-Sep-06 Release date: 25-Sep-07

Protein chain

Q9P868  (Q9P868_PIREQ) -  Endoglucanase 45A

Seq: 410 a.a.

Struc: 100 a.a.*

* PDB and UniProt seqs differ at 2 residue positions (black crosses)

 Gene Ontology (GO) functional annotation 

• Biochemical function: protein domain specific binding (1 term)

DOI no: 10.1016/j.jmb.2007.08.007

J Mol Biol 373:612-622 (2007)

PubMed id: 17869267

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

T.Nagy, R.B.Tunnicliffe, L.D.Higgins, C.Walters, H.J.Gilbert, M.P.Williamson.

ABSTRACT

The assembly into supramolecular complexes of proteins having complementary activities is central to cellular function. One such complex of considerable biological and industrial significance is the plant cell wall-degrading apparatus of anaerobic microorganisms, termed the cellulosome. A central feature of bacterial cellulosomes is a large non-catalytic protein, the scaffoldin, which contains multiple cohesin domains. An array of digestive enzymes is incorporated into the cellulosome through the interaction of the dockerin domains, present in the catalytic subunits, with the cohesin domains that are present in the scaffoldin. By contrast, in anaerobic fungi, such as Piromyces equi, the dockerins of cellulosomal enzymes are often present in tandem copies; however, the identity of the cognate cohesin domains in these organisms is unclear, hindering further biotechnological development of the fungal cellulosome. Here, we characterise the solution structure and function of a double-dockerin construct from the P. equi endoglucanase Cel45A. We show that the two domains are connected by a flexible linker that is short enough to keep the binding sites of the two domains on adjacent surfaces, and allows the double-dockerin construct to bind more tightly to cellulosomes than a single domain and with greater coverage. The double dockerin binds to the GH3 beta-glucosidase component of the fungal cellulosome, which is thereby identified as a potential scaffoldin.

Selected figure(s)

Figure 3.
Figure 3. Structure of the double dockerin from Cel45A (a) shown as a cartoon, with β-sheets numbered, and with the two binding sites indicated by the side-chains of the key residues (see below); (b) an ensemble of 30 structures overlaid on the N-terminal domain; and (c) an ensemble of 30 structures overlaid on the C-terminal domain.

Figure 5.
Figure 5. ^15N relaxation data for the double dockerin.

The above figures are reprinted by permission from Elsevier: J Mol Biol (2007, 373, 612-622) copyright 2007.

Figures were selected by an automated process.