PDBsum entry 4cdh

Immune system

PDB id: 4cdh

Contents

Protein chains

206 a.a.

Ligands

NAG-NAG-BMA-MAN-NAG-GAL-MAN-NAG-GAL-FUL

NAG-NAG-BMA-MAN-NAG-GAL-MAN-NAG

Waters ×82

PDB id:

4cdh

Name:

Immune system

Title:

Crystallographic structure of the human igg1 alpha 2-6 sialilated fc- fragment

Structure:

Ig gamma-1 chain c region. Chain: a, b. Fragment: fc, residues 101-330. Synonym: igg1

Source:

Homo sapiens. Organism_taxid: 9606

Resolution:

2.30Å R-factor: 0.236 R-free: 0.282

Authors:

N.Silva-Martin,S.G.Bartual,J.A.Hermoso

Key ref:

N.Silva-Martín et al. (2014). Structural basis for selective recognition of endogenous and microbial polysaccharides by macrophage receptor SIGN-R1. Structure, 22, 1595-1606. PubMed id: 25450767 DOI: 10.1016/j.str.2014.09.001

Date:

31-Oct-13 Release date: 12-Nov-14

Protein chains

P01857  (IGHG1_HUMAN) -  Immunoglobulin heavy constant gamma 1 from Homo sapiens

Seq: 399 a.a.

Struc: 206 a.a.

DOI no: 10.1016/j.str.2014.09.001

Structure 22:1595-1606 (2014)

PubMed id: 25450767

Structural basis for selective recognition of endogenous and microbial polysaccharides by macrophage receptor SIGN-R1.

N.Silva-Martín, S.G.Bartual, E.Ramírez-Aportela, P.Chacón, C.G.Park, J.A.Hermoso.

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.