4CAJ

Crystallographic structure of the mouse SIGN-R1 CRD domain in complex with sialic acid

Summary for 4CAJ

• Entry DOI: 10.2210/pdb4caj/pdb
• Related: 4C9F
• Descriptor: CD209 ANTIGEN-LIKE PROTEIN B, CALCIUM ION, SULFATE ION, ... (6 entities in total)
• Functional Keywords: c-lectin crd, sign-r1, immune system, capsular polysaccharide
• Biological source: MUS MUSCULUS (HOUSE MOUSE)
• Total number of polymer chains: 4
• Total formula weight: 75934.12

Authors

Silva-Martin, N.,Bartual, S.G.,Hermoso, J.A. (deposition date: 2013-10-08, release date: 2014-10-15, Last modification date: 2024-10-16)

Primary citation

Silva-Martin, N.,Bartual, S.G.,Rodriguez, A.,Ramirez, E.,Chacon, P.,Anthony, R.M.,Park, C.G.,Hermoso, J.A.
Structural Basis for Selective Recognition of Endogenous and Microbial Polysaccharides by Macrophage Receptor Sign-R1
Structure, 22:1595-, 2014

PubMed Abstract: SIGN-R1 is a principal receptor for microbial polysaccharides uptake and is responsible for C3 fixation via an unusual complement activation pathway on splenic marginal zone macrophages. In these macrophages, SIGN-R1 is also involved in anti-inflammatory activity of intravenous immunoglobulin by direct interaction with sialylated Fcs. The high-resolution crystal structures of SIGN-R1 carbohydrate recognition domain and its complexes with dextran sulfate or sialic acid, and of the sialylated Fc antibody provide insights into SIGN-R1’s selective recognition of a-2,6-sialylated glycoproteins. Unexpectedly, an additional binding site has been found in the SIGNR1 carbohydrate recognition domain, structurally separate from the calcium-dependent carbohydrate-binding site. This secondary binding site could bind repetitive molecular patterns, as observed in microbial polysaccharides, in a calcium-independent manner. These two binding sites may allow SIGNR1 to simultaneously bind both immune glycoproteins and microbial polysaccharide components, accommodating SIGN-R1’s ability to relate the recognition of microbes to the activation of the classical complement pathway.

PubMed: 25450767
DOI: 10.1016/J.STR.2014.09.001

Experimental method

X-RAY DIFFRACTION (2.191 Å)