 |
PDBsum entry 1b08
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
 |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Sugar binding protein
|
PDB id
|
|
|
|
1b08
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
 |
Contents |
 |
|
|
|
|
|
|
|
|
|
|
|
|
* Residue conservation analysis
|
|
|
|
|
References listed in PDB file
|
|
|
Key reference
|
|
|
Title
|
|
Crystal structure of the trimeric alpha-Helical coiled-Coil and the three lectin domains of human lung surfactant protein d.
|
|
|
Authors
|
|
K.Håkansson,
N.K.Lim,
H.J.Hoppe,
K.B.Reid.
|
|
|
Ref.
|
|
Structure, 1999,
7,
255-264.
[DOI no: ]
|
|
|
PubMed id
|
|
|
|
|
|
Abstract
|
|
|
BACKGROUND: Human lung surfactant protein D (hSP-D) belongs to the collectin
family of C-type lectins and participates in the innate immune surveillance
against microorganisms in the lung through recognition of carbohydrate ligands
present on the surface of pathogens. The involvement of this protein in innate
immunity and the allergic response make it the subject of much interest.
RESULTS: We have determined the crystal structure of a trimeric fragment of
hSP-D at 2.3 A resolution. The structure comprises an alpha-helical coiled-coil
and three carbohydrate-recognition domains (CRDs). An interesting deviation from
symmetry was found in the projection of a single tyrosine sidechain into the
centre of the coiled-coil; the asymmetry of this residue influences the
orientation of one of the adjacent CRDs. The cleft between the three CRDs
presents a large positively charged surface. CONCLUSIONS: The fold of the CRD of
hSP-D is similar to that of the mannan-binding protein (MBP), but its
orientation relative to the alpha-helical coiled-coil region differs somewhat to
that seen in the MBP structure. The novel central packing of the tyrosine
sidechain within the coiled-coil and the resulting asymmetric orientation of the
CRDs has unexpected functional implications. The positively charged surface
might facilitate binding to negatively charged structures, such as
lipopolysaccharides.
|
|
|
|
|
|
Figure 7.
Figure 7. The mainchain fold of hSP-D with consensus motifs
highlighted: DGGS is in red and RACGEKR is in blue. Calcium ions
are depicted as green spheres. (The figure was produced using
the program RIBBONS [39].)
|
|
|
|
|
|
The above figure is
reprinted
by permission from Cell Press:
Structure
(1999,
7,
255-264)
copyright 1999.
|
|
|
|
|
|
|
