PDBsum entry 2wnp

Immune system

PDB id: 2wnp

Contents

Protein chain

217 a.a. *

Ligands

IPA

Metals

_CA

Waters ×243

* Residue conservation analysis

PDB id:

2wnp

Name:

Immune system

Title:

M-ficolin mutant y271f

Structure:

Ficolin-1. Chain: f. Fragment: fbg domain, residues 110-326. Synonym: ficolin-a, ficolin-alpha, m-ficolin, collagen/fibrinogen domain-containing protein 1. Engineered: yes. Mutation: yes

Source:

Homo sapiens. Human. Organism_taxid: 9606. Expressed in: spodoptera frugiperda. Expression_system_taxid: 7108

Resolution:

1.21Å R-factor: 0.178 R-free: 0.191

Authors:

E.Gout,V.Garlatti,D.F.Smith,M.Lacroix,C.Dumestre-Perard,T.Lunardi, G.J.Arlaud,C.Gaboriaud,N.M.Thielens

Key ref:

E.Gout et al. (2010). Carbohydrate recognition properties of human ficolins: glycan array screening reveals the sialic acid binding specificity of M-ficolin. J Biol Chem, 285, 6612-6622. PubMed id: 20032467

Date:

16-Jul-09 Release date: 22-Dec-09

Protein chain

O00602  (FCN1_HUMAN) -  Ficolin-1 from Homo sapiens

Seq: 326 a.a.

Struc: 217 a.a.*

* PDB and UniProt seqs differ at 1 residue position (black cross)

J Biol Chem 285:6612-6622 (2010)

PubMed id: 20032467

Carbohydrate recognition properties of human ficolins: glycan array screening reveals the sialic acid binding specificity of M-ficolin.

E.Gout, V.Garlatti, D.F.Smith, M.Lacroix, C.Dumestre-Pérard, T.Lunardi, L.Martin, J.Y.Cesbron, G.J.Arlaud, C.Gaboriaud, N.M.Thielens.

ABSTRACT

Ficolins are oligomeric innate immune recognition proteins consisting of a collagen-like region and a fibrinogen-like recognition domain that bind to pathogen- and apoptotic cell-associated molecular patterns. To investigate their carbohydrate binding specificities, serum-derived L-ficolin and recombinant H- and M-ficolins were fluorescently labeled, and their carbohydrate binding ability was analyzed by glycan array screening. L-ficolin preferentially recognized disulfated N-acetyllactosamine and tri- and tetrasaccharides containing terminal galactose or N-acetylglucosamine. Binding was sensitive to the position and orientation of the bond between N-acetyllactosamine and the adjacent carbohydrate. No significant binding of H-ficolin to any of the 377 glycans probed could be detected, providing further evidence for its poor lectin activity. M-ficolin bound preferentially to 9-O-acetylated 2-6-linked sialic acid derivatives and to various glycans containing sialic acid engaged in a 2-3 linkage. To further investigate the structural basis of sialic acid recognition by M-ficolin, point mutants were produced in which three residues of the fibrinogen domain were replaced by their counterparts in L-ficolin. Mutations G221F and A256V inhibited binding to the 9-O-acetylated sialic acid derivatives, whereas Y271F abolished interaction with all sialic acid-containing glycans. The crystal structure of the Y271F mutant fibrinogen domain was solved, showing that the mutation does not alter the structure of the ligand binding pocket. These analyses reveal novel ficolin ligands such as sulfated N-acetyllactosamine (L-ficolin) and gangliosides (M-ficolin) and provide precise insights into the sialic acid binding specificity of M-ficolin, emphasizing the essential role of Tyr(271) in this respect.