PDBsum entry 1is4

Sugar binding protein

PDB id: 1is4

Contents

Protein chain

134 a.a. *

Ligands

BGC-GAL

Waters ×91

* Residue conservation analysis

PDB id:

1is4

Name:

Sugar binding protein

Title:

Lactose-liganded congerin ii

Structure:

Congerin ii. Chain: a. Synonym: beta-galactoside-binding lectin 2. Engineered: yes

Source:

Conger myriaster. Whitespotted conger. Organism_taxid: 7943. Expressed in: escherichia coli. Expression_system_taxid: 562.

Biol. unit:

Tetramer (from PDB file)

Resolution:

1.90Å R-factor: 0.166 R-free: 0.217

Authors:

T.Shirai,Y.Matsui,C.Shionyu-Mitsuyama,T.Yamane,H.Kamiya,C.Ishii, T.Ogawa,K.Muramoto

Key ref:

T.Shirai et al. (2002). Crystal structure of a conger eel galectin (congerin II) at 1.45A resolution: implication for the accelerated evolution of a new ligand-binding site following gene duplication. J Mol Biol, 321, 879-889. PubMed id: 12206768 DOI: 10.1016/S0022-2836(02)00700-3

Date:

12-Nov-01 Release date: 18-Sep-02

Protein chain

Q9YIC2  (LEG2_CONMY) -  Congerin-2 from Conger myriaster

Seq: 136 a.a.

Struc: 134 a.a.

Enzyme reactions

• Enzyme class: E.C.?

DOI no: 10.1016/S0022-2836(02)00700-3

J Mol Biol 321:879-889 (2002)

PubMed id: 12206768

Crystal structure of a conger eel galectin (congerin II) at 1.45A resolution: implication for the accelerated evolution of a new ligand-binding site following gene duplication.

T.Shirai, Y.Matsui, C.Shionyu-Mitsuyama, T.Yamane, H.Kamiya, C.Ishii, T.Ogawa, K.Muramoto.

ABSTRACT

The crystal structure of congerin II, a galectin family lectin from conger eel, was determined at 1.45A resolution. The previously determined structure of its isoform, congerin I, had revealed a fold evolution via strand swap; however, the structure of congerin II described here resembles other prototype galectins. A comparison of the two congerin genes with that of several other galectins suggests acceralated evolution of both congerin genes following gene duplication. The presence of a Mes (2-[N-morpholino]ethanesulfonic acid) molecule near the carbohydrate-binding site in the crystal structure points to the possibility of an additional binding site in congerin II. The binding site consists of a group of residues that had been replaced following gene duplication suggesting that the binding site was built under selective pressure. Congerin II may be a protein specialized for biological defense with an affinity for target carbohydrates on parasites' cell surface.

Selected figure(s)

Figure 2.
Figure 2. (a) The carbohydrate-binding site of congerin II. The side-chains that bind the lactose or Mes molecules are shown in blue. The hydrogen bonds between protein and ligand are shown in yellow. The water molecule mediating hydrogen bonding is represented as a red sphere. Omit electron density map around the ligand molecules is superposed as purple network. The map was phased by the final model without the ligand atoms, and contoured at 3.0s level. (b) Comparison between the binding sites of congerin II in ternary complex (blue) and in apo form (orange). The spheres are water molecules in the apo form; hydrogen bonds are shown in yellow.

Figure 7.
Figure 7. A comparison of carbohydrate-binding sites of congerin II (blue), congerin I (orange) and bovine galectin-1 (gray). The residues are labeled as congerin II amino acid and residue number: corresponding amino acid of congerin I: corresponding amino acid of galectin-1.

The above figures are reprinted by permission from Elsevier: J Mol Biol (2002, 321, 879-889) copyright 2002.

Figures were selected by an automated process.