PDBsum entry 3dui

Sugar binding protein

PDB id: 3dui

Contents

Protein chains

132 a.a. *

Ligands

BME ×2

Waters ×98

* Residue conservation analysis

PDB id:

3dui

Name:

Sugar binding protein

Title:

Crystal structure of the oxidized cg-1b: an adhesion/growth-regulatory lectin from chicken

Structure:

Beta-galactoside-binding lectin. Chain: a, b. Synonym: 14 kda lectin, c-14, cg-1b (cg-14). Engineered: yes

Source:

Gallus gallus. Bantam,chickens. Organism_taxid: 9031. Expressed in: escherichia coli. Expression_system_taxid: 562.

Resolution:

2.10Å R-factor: 0.238 R-free: 0.286

Authors:

A.Romero,M.I.F.Lopez-Lucendo,D.Solis,H.-J.Gabius

Key ref:

M.F.López-Lucendo et al. (2009). Homodimeric chicken galectin CG-1B (C-14): Crystal structure and detection of unique redox-dependent shape changes involving inter- and intrasubunit disulfide bridges by gel filtration, ultracentrifugation, site-directed mutagenesis, and peptide mass fingerprinting. J Mol Biol, 386, 366-378. PubMed id: 18848566 DOI: 10.1016/j.jmb.2008.09.054

Date:

17-Jul-08 Release date: 30-Jun-09

Protein chains

P07583  (LEG4_CHICK) -  Beta-galactoside-binding lectin from Gallus gallus

Seq: 135 a.a.

Struc: 132 a.a.

DOI no: 10.1016/j.jmb.2008.09.054

J Mol Biol 386:366-378 (2009)

PubMed id: 18848566

Homodimeric chicken galectin CG-1B (C-14): Crystal structure and detection of unique redox-dependent shape changes involving inter- and intrasubunit disulfide bridges by gel filtration, ultracentrifugation, site-directed mutagenesis, and peptide mass fingerprinting.

M.F.López-Lucendo, D.Solís, J.L.Sáiz, H.Kaltner, R.Russwurm, S.André, H.J.Gabius, A.Romero.

ABSTRACT

Intrafamily gene diversification has led to three prototype galectins in chicken [i.e., chicken galectin (CG)-1A, CG-1B, and CG-2] that show distinct expression profiles and developmental regulation. In order to pinpoint structural disparities among them, we determined the crystal structure of CG-1B. Alteration of the position of the Trp ring in the lectin site and the presence of only two ordered water molecules therein, as well as changes in the interface region between the two subunits, set the structure of CG-1B clearly apart from that of CG-1A. Intriguingly, the unique presence of two Cys residues at positions 2 and 7 in the N-terminal region translated into formation of an intersubunit disulfide bridge between the Cys7 residues of the homodimer in the crystal. In solution, oxidation is associated with significant shape changes in the dimeric protein and the additional occurrence of a compacted form with an intrasubunit disulfide bridge between Cys2 and Cys7. The single-site mutant C7S/C7V was not subjected to such changes, supporting the crucial role of Cys7 in redox-dependent shape changes. These results point to the functional significance of the distinctive presence of the two Cys residues in the N-terminal region of CG-1B.

Selected figure(s)

Figure 2.
Fig. 2. CG-1B structure. (a) Ribbon representation of CG-1B, shown in standard orientation, with two identical monomers related by an NCS axis. (b) Same as (a) after a 90° horizontal anticlockwise rotation showing the typical “jelly-roll” topology. For clarity, β-strands are labeled only in one monomer. All structure figures were prepared using the program PyMOL (Delano Scientific).

Figure 5.
Fig. 5. The carbohydrate-binding site. Stereoview of the binding site in CG-1B (orange) superimposed with the carbohydrate recognition domains of CG-1A (yellow) and hGal-1 (purple). The amino acid residues involved in ligand recognition, namely, His45, Asn47, Arg49, Val60, Asn62, Trp69, Glu72, and Arg74, are shown in ball-and-stick representation, and the position of bound water molecules is shown as spheres.

The above figures are reprinted by permission from Elsevier: J Mol Biol (2009, 386, 366-378) copyright 2009.

Figures were selected by the author.