PDBsum entry 1oxc

Sugar binding protein

PDB id: 1oxc

Contents

Protein chains

114 a.a. *

Ligands

FUL ×2

FUC ×4

SO4

Metals

_CA ×8

Waters ×656

* Residue conservation analysis

PDB id:

1oxc

Name:

Sugar binding protein

Title:

Lecb (pa-lii) in complex with fucose

Structure:

Hypothetical protein lecb. Chain: a, b, c, d. Synonym: lecb. Engineered: yes

Source:

Pseudomonas aeruginosa. Organism_taxid: 287. Gene: lecb. Expressed in: escherichia coli. Expression_system_taxid: 562.

Biol. unit:

Tetramer (from PQS)

Resolution:

1.20Å R-factor: 0.174 R-free: 0.185

Authors:

R.Loris,D.Tielker,K.-E.Jaeger,L.Wyns

Key ref:

R.Loris et al. (2003). Structural basis of carbohydrate recognition by the lectin LecB from Pseudomonas aeruginosa. J Mol Biol, 331, 861-870. PubMed id: 12909014 DOI: 10.1016/S0022-2836(03)00754-X

Date:

02-Apr-03 Release date: 09-Sep-03

Protein chains

Q9HYN5  (Q9HYN5_PSEAE) -  Fucose-binding lectin PA-IIL from Pseudomonas aeruginosa (strain ATCC 15692 / DSM 22644 / CIP 104116 / JCM 14847 / LMG 12228 / 1C / PRS 101 / PAO1)

Seq: 115 a.a.

Struc: 114 a.a.

DOI no: 10.1016/S0022-2836(03)00754-X

J Mol Biol 331:861-870 (2003)

PubMed id: 12909014

Structural basis of carbohydrate recognition by the lectin LecB from Pseudomonas aeruginosa.

R.Loris, D.Tielker, K.E.Jaeger, L.Wyns.

ABSTRACT

The crystal structure of Pseudomonas aeruginosa fucose-specific lectin LecB was determined in its metal-bound and metal-free state as well as in complex with fucose, mannose and fructopyranose. All three monosaccharides bind isosterically via direct interactions with two calcium ions as well as direct hydrogen bonds with several side-chains. The higher affinity for fucose is explained by the details of the binding site around C6 and O1 of fucose. In the mannose and fructose complexes, a carboxylate oxygen atom and one or two hydroxyl groups are partly shielded from solvent upon sugar binding, preventing them from completely fulfilling their hydrogen bonding potential. In the fucose complex, no such defects are observed. Instead, C6 makes favourable interactions with a small hydrophobic patch. Upon demetallization, the C terminus as well as the otherwise rigid metal-binding loop become more mobile and adopt multiple conformations.

Selected figure(s)

Figure 1.
Figure 1. Overall structure of LecB. (a) Ribbon representation of the LecB monomer showing one sheet in blue and one in green. The two calcium ions are shown as red spheres. (b) The LecB tetramer with each monomer shown in a different colour. Each monomer is labeled A, B, C or D according to the nomenclature used in the text. (c) Conserved water molecules in the native, calcium-bound LecB structures are shown superimposed on a C^a trace of the LecB tetramer. The view is identical with that in (b). The water molecules that occupy the waste of the tetramer are shown in dark blue. Two completely buried water molecules are shown in red. Orange water molecules are located at the otherwise largely hydrophobic AB interface. Conserved water molecules located close to the monosaccharide binding site are coloured green. The remaining conserved water molecules that are scattered over the surface of the tetramer are coloured in light blue.

Figure 4.
Figure 4. Comparison of the carbohydrate-binding site of LecB (left) and MBP-A (right). Mannose is shown in red, fucose in orange and the calcium ions in green. Residues that contribute to hydrophobic stacking on the sugar rings are shown in blue ball-and-stick.

The above figures are reprinted by permission from Elsevier: J Mol Biol (2003, 331, 861-870) copyright 2003.

Figures were selected by an automated process.