2J3F: L-Ficolin Complexed To N-Acetyl-D-Galactosamine

Citation:
Abstract
Innate immunity relies critically upon the ability of a few pattern recognition molecules to sense molecular markers on pathogens, but little is known about these interactions at the atomic level. Human L- and H-ficolins are soluble oligomeric defence proteins with lectin-like activity, assembled from collagen fibers prolonged by fibrinogen-like recognition domains. The X-ray structures of their trimeric recognition domains, alone and in complex with various ligands, have been solved to resolutions up to 1.95 and 1.7 A, respectively. Both domains have three-lobed structures with clefts separating the distal parts of the protomers. Ca(2+) ions are found at sites homologous to those described for tachylectin 5A (TL5A), an invertebrate lectin. Outer binding sites (S1) homologous to the GlcNAc-binding pocket of TL5A are present in the ficolins but show different structures and specificities. In L-ficolin, three additional binding sites (S2-S4) surround the cleft. Together, they define an unpredicted continuous recognition surface able to sense various acetylated and neutral carbohydrate markers in the context of extended polysaccharides such as 1,3-beta-D-glucan, as found on microbial or apoptotic surfaces.
PDB ID: 2J3FDownload
MMDB ID: 53660
PDB Deposition Date: 2006/8/21
Updated in MMDB: 2007/10
Experimental Method:
x-ray diffraction
Resolution: 2.8  Å
Source Organism:
Similar Structures:
Biological Unit for 2J3F: trimeric; determined by author and by software (PQS)
Molecular Components in 2J3F
Label Count Molecule
Proteins (3 molecules)
3
Ficolin-2(Gene symbol: FCN2)
Molecule annotation
Chemicals (8 molecules)
1
3
2
2
3
1
4
1
5
1
* Click molecule labels to explore molecular sequence information.

Citing MMDB
.