PDBsum entry 1qos

Lectin

PDB id: 1qos

Contents

Protein chains

237 a.a. *

Ligands

NAG-NAG ×2

NAG

Metals

_CA ×2

_MN ×2

* Residue conservation analysis

PDB id:

1qos

Name:

Lectin

Title:

Lectin uea-ii complexed with chitobiose

Structure:

Chitin binding lectin, uea-ii. Chain: a, b

Source:

Ulex europaeus. Furze. Organism_taxid: 3902. Organ: seed

Biol. unit:

Homo-Tetramer (from PDB file)

Resolution:

2.95Å R-factor: 0.189 R-free: 0.223

Authors:

R.Loris,H.De Greve,M.-H.Dao-Thi,J.Messens,A.Imberty,L.Wyns

Key ref:

R.Loris et al. (2000). Structural basis of carbohydrate recognition by lectin II from Ulex europaeus, a protein with a promiscuous carbohydrate-binding site. J Mol Biol, 301, 987. PubMed id: 10966800 DOI: 10.1006/jmbi.2000.4016

Date:

16-Nov-99 Release date: 07-Feb-00

Protein chains

Q9FVF8  (Q9FVF8_ULEEU) -  Lectin II (Fragment) from Ulex europaeus

Seq: 258 a.a.

Struc: 237 a.a.*

* PDB and UniProt seqs differ at 6 residue positions (black crosses)

DOI no: 10.1006/jmbi.2000.4016

J Mol Biol 301:987 (2000)

PubMed id: 10966800

Structural basis of carbohydrate recognition by lectin II from Ulex europaeus, a protein with a promiscuous carbohydrate-binding site.

R.Loris, H.De Greve, M.H.Dao-Thi, J.Messens, A.Imberty, L.Wyns.

ABSTRACT

Protein-carbohydrate interactions are the language of choice for inter- cellular communication. The legume lectins form a large family of homologous proteins that exhibit a wide variety of carbohydrate specificities. The legume lectin family is therefore highly suitable as a model system to study the structural principles of protein-carbohydrate recognition. Until now, structural data are only available for two specificity families: Man/Glc and Gal/GalNAc. No structural data are available for any of the fucose or chitobiose specific lectins.The crystal structure of Ulex europaeus (UEA-II) is the first of a legume lectin belonging to the chitobiose specificity group. The complexes with N-acetylglucosamine, galactose and fucosylgalactose show a promiscuous primary binding site capable of accommodating both N-acetylglucos amine or galactose in the primary binding site. The hydrogen bonding network in these complexes can be considered suboptimal, in agreement with the low affinities of these sugars. In the complexes with chitobiose, lactose and fucosyllactose this suboptimal hydrogen bonding network is compensated by extensive hydrophobic interactions in a Glc/GlcNAc binding subsite. UEA-II thus forms the first example of a legume lectin with a promiscuous binding site and illustrates the importance of hydrophobic interactions in protein-carbohydrate complexes. Together with other known legume lectin crystal structures, it shows how different specificities can be grafted upon a conserved structural framework.

Selected figure(s)

Figure 3.
Figure 3. Comparison of the tetramer formed by UEA-II and DBL. (a) Ribbon diagram of the UEA-II tetramer. (b) Ribbon diagram of the DBL tetramer showing the C-terminal helix in red. (c) Close-up of the DB58-like interface of UEA-II showing the disulphide linkage between Cys184 of two adjacent monomers. The side-chains of Asp169, Val171, Thr173 and Arg175 (upper strand), Ser180 Thr182, Cys184 and Ser186 (middle strand) and Ser193, Ile195 and Thr197 (lower strand) are shown in ball-and-stick representation. Cys184 is labelled. (d) Similar view of the DB58-like interface of the DBL tetramer. The side-chains of Glu163, Leu165, Thr167 and Asn169 (upper strand), Leu174, Val176, Ser178 and Val180 (middle strand) and Ser187, Ile189 and Ser191 (lower strand) are shown in ball-and-stick representation. Ser178 (the equivalent of Cys184 in UEA-II) is labelled.

Figure 7.
Figure 7. Schematic drawing of oligosaccharide recognition by UEA-II. (a) Binding of GlcNAc and chitobiose. (b) Binding of galactose, lactose, fucosylgalactose and fucosyllactose.

The above figures are reprinted by permission from Elsevier: J Mol Biol (2000, 301, 987-0) copyright 2000.

Figures were selected by an automated process.