2DF3

The structure of Siglec-7 in complex with alpha(2,3)/alpha(2,6) disialyl lactotetraosyl 2-(trimethylsilyl)ethyl

Summary for 2DF3

• Entry DOI: 10.2210/pdb2df3/pdb
• Related: 1O7S
• Descriptor: Sialic acid-binding Ig-like lectin 7, N-acetyl-alpha-neuraminic acid-(2-3)-beta-D-galactopyranose-(1-3)-[N-acetyl-alpha-neuraminic acid-(2-6)]2-acetamido-2-deoxy-beta-D-glucopyranose, 2-acetamido-2-deoxy-beta-D-glucopyranose, ... (5 entities in total)
• Functional Keywords: siglec, sialic acid, ganglioside, cell adhesion
• Biological source: Homo sapiens (Human)
• Total number of polymer chains: 1
• Total formula weight: 15963.52

Authors

Attrill, H. (deposition date: 2006-02-23, release date: 2006-06-20, Last modification date: 2023-10-25)

Primary citation

Attrill, H.,Takazawa, H.,Witt, S.,Kelm, S.,Isecke, R.,Brossmer, R.,Ando, T.,Ishida, H.,Kiso, M.,Crocker, P.R.,van Aalten, D.M.F.
The structure of siglec-7 in complex with sialosides: leads for rational structure-based inhibitor design
Biochem.J., 397:271-278, 2006

PubMed Abstract: Siglecs (sialic acid binding Ig-like lectins) are transmembrane receptors for sialylated glycoconjugates that modulate cellular interactions and signalling events in the haematopoietic, immune and nervous systems. Siglec-7 is a structural prototype for the recently described family of immune inhibitory CD33-related siglecs and is predominantly expressed on natural killer cells and monocytes, as well as subsets of CD8 T-cells. Siglec-specific inhibitors are desired for the detection of masked and unmasked forms of siglecs, to aid in dissection of signalling pathways and as tools to investigate siglecs as potential therapeutic targets. As a first step towards this end, we present the crystal structure of siglec-7 in complex with a sialylated ligand, the ganglioside analogue DSLc4 [alpha(2,3)/alpha(2,6) disialyl lactotetraosyl 2-(trimethylsilyl)ethyl], which allows for a detailed description of the binding site, required for structure-guided inhibitor design. Mutagenesis and binding assays were used to demonstrate a key structural role for Lys131, a residue that changes conformation upon sialic acid binding. Differences between the binding sites of siglec family members were then exploited using alpha-methyl Neu5Ac (N-acetylneuraminic acid) as a basic scaffold. A co-crystal of siglec-7 in complex with the sialoside inhibitor, oxamido-Neu5Ac [methyl alpha-9-(amino-oxalyl-amino)-9-deoxy-Neu5Ac] and inhibition data for the sialosides gives clear leads for future inhibitor design.

PubMed: 16623661
DOI: 10.1042/BJ20060103

Experimental method

X-RAY DIFFRACTION (1.9 Å)