 |
PDBsum entry 1oxc
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
 |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Sugar binding protein
|
PDB id
|
|
|
|
1oxc
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
 |
Contents |
 |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
* Residue conservation analysis
|
|
|
|
|
References listed in PDB file
|
|
|
Key reference
|
|
|
Title
|
|
Structural basis of carbohydrate recognition by the lectin lecb from pseudomonas aeruginosa.
|
|
|
Authors
|
|
R.Loris,
D.Tielker,
K.E.Jaeger,
L.Wyns.
|
|
|
Ref.
|
|
J Mol Biol, 2003,
331,
861-870.
[DOI no: ]
|
|
|
PubMed id
|
|
|
|
|
|
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.
|
|
|
|
|
|
|
|
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.
|
|
|
|
|
|
|
