PDBsum entry 2kmb

Lectin

PDB id: 2kmb

Contents

Protein chains

149 a.a. *

Ligands

MAG-GAL-SIA-FUC ×2

NAG-GAL-SIA-FUC

Metals

_CL ×3

_CA ×10

Waters ×458

* Residue conservation analysis

References listed in PDB file

Key reference

Title

Structure of a selectin-Like mutant of mannose-Binding protein complexed with sialylated and sulfated lewis(x) oligosaccharides.

Authors

K.K.Ng, W.I.Weis.

Ref.

Biochemistry, 1997, 36, 979-988. [DOI no: 10.1021/bi962564e]

PubMed id

9033386

Note In the PDB file this reference is annotated as "TO BE PUBLISHED". The citation details given above were identified by an automated search of PubMed on title and author names, giving a perfect match.

Abstract

Rat serum mannose-binding protein in which residues 211-213 have been changed to the Lys-Lys-Lys sequence found in E-selectin binds HL-60 cells and the oligosaccharide 3'-NeuAc-Le(x). To understand how this mutant, designated K3, mimics the carbohydrate-binding properties of E-selectin, structures of K3 alone and in complexes with 3'-NeuAc-Le(x), 3'-sulfo-Le(x) and 4'-sulfo-Le(x) have been determined at 1.95-2.1 A resolution by X-ray crystallography. The region of K3 that interacts with bound oligosaccharides superimposes closely with the corresponding region of unliganded E-selectin. In each of the oligosaccharide-protein complexes, the 2- and 3-OH of Fuc coordinate Ca2+ and form a network of cooperative hydrogen bonds with amino acid side chains that also coordinate the Ca2+. Lys211 of the K3 mutant, which corresponds to Lys111 of E-selectin, interacts with each of the three bound ligands: the N zeta atom donates a hydrogen bond to the 4-OH of Gal in 3'-NeuAc-Le(x), forms a water-mediated hydrogen bond with the 4-OH of Gal in 3'-sulfo-Le(x), and forms a salt bridge with the sulfate group of 4'-sulfo-Le(x). Lys213 packs against an otherwise exposed aromatic residue and forms a water-mediated hydrogen bond with Lys211 which may help to position that residue for interactions with bound oligosaccharides. These structures are consistent with previous mutagenesis and chemical modification studies which demonstrate the importance of the Ca2+ ligands as well as Lys111 and Lys113 for carbohydrate binding in the selectins, and they provide a structural basis for understanding the selective recognition of negatively charged Le(x) derivatives by the selectins.

Secondary reference #1

Title

Introduction of selectin-Like binding specificity into a homologous mannose-Binding protein.

Authors

O.Blanck, S.T.Iobst, C.Gabel, K.Drickamer.

Ref.

J Biol Chem, 1996, 271, 7289-7292.

PubMed id

8631744

Secondary reference #2

Title

Trimeric structure of a c-Type mannose-Binding protein.

Authors

W.I.Weis, K.Drickamer.

Ref.

Structure, 1994, 2, 1227-1240. [DOI no: 10.1016/S0969-2126(94)00124-3]

PubMed id

7704532

Figure 7.
Figure 7. A portion of the neck–CRD interface, shown with the 1.25σ contour of the final 2F[o]–F[c] map. Conserved hydrophobic residues are labeled; the residues come from the protomer whose number precedes the amino acid name. Figure 7. A portion of the neck–CRD interface, shown with the 1.25σ contour of the final 2F[o]–F[c] map. Conserved hydrophobic residues are labeled; the residues come from the protomer whose number precedes the amino acid name.

Figure 8.
Figure 8. Representative sequences of the neck region and portions of the CRDs following the last Gly-X-Y repeat taken from various subgroups of collectins. RA, rat; HU, human. The a and d positions of the heptadrepeats are indicated. Sites of introns and the sites of subtilisin digestion that releases the carboxy-terminal CRDs of MBPs are underlined. Residues inthe neck–CRD interface (see Table 2) are denoted with asterisks. Sequences and intron positions are derived from [19, 44, 61, 62, 63, 64 and 65]. Figure 8. Representative sequences of the neck region and portions of the CRDs following the last Gly-X-Y repeat taken from various subgroups of collectins. RA, rat; HU, human. The a and d positions of the heptadrepeats are indicated. Sites of introns and the sites of subtilisin digestion that releases the carboxy-terminal CRDs of MBPs are underlined. Residues inthe neck–CRD interface (see [3]Table 2) are denoted with asterisks. Sequences and intron positions are derived from [[4]19, [5]44, [6]61, [7]62, [8]63, [9]64 and [10]65].

The above figures are reproduced from the cited reference with permission from Cell Press