PDBsum entry 3a0e

Sugar binding protein

PDB id: 3a0e

Contents

Protein chain

110 a.a. *

Ligands

MAN-MAN

SO4 ×5

Waters ×136

* Residue conservation analysis

PDB id:

3a0e

Name:

Sugar binding protein

Title:

Crystal structure of polygonatum cyrtonema lectin (pcl) complexed with dimannoside

Structure:

Mannose/sialic acid-binding lectin. Chain: a. Fragment: unp residues 29-138

Source:

Polygonatum cyrtonema. Organism_taxid: 195526. Strain: hua

Resolution:

2.00Å R-factor: 0.190 R-free: 0.212

Authors:

J.Ding,D.C.Wang

Key ref:

J.Ding et al. (2010). Crystal structures of a novel anti-HIV mannose-binding lectin from Polygonatum cyrtonema Hua with unique ligand-binding property and super-structure. J Struct Biol, 171, 309-317. PubMed id: 20546901

Date:

16-Mar-09 Release date: 16-Mar-10

Protein chain

Q8L568  (Q8L568_9ASPA) -  Mannose/sialic acid-binding lectin from Polygonatum cyrtonema

Seq: 160 a.a.

Struc: 110 a.a.*

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

J Struct Biol 171:309-317 (2010)

PubMed id: 20546901

Crystal structures of a novel anti-HIV mannose-binding lectin from Polygonatum cyrtonema Hua with unique ligand-binding property and super-structure.

J.Ding, J.Bao, D.Zhu, Y.Zhang, D.C.Wang.

ABSTRACT

Polygonatum cyrtonema lectin (PCL) is a novel anti-HIV mannose-binding lectin from Galanthus nivalis agglutinin (GNA)-related lectin family. Crystal structures of ligand-free PCL and its complexes with monomannoside and alpha1-3 dimannoside have been determined. The ligand-free PCL is dimeric, with both subunits adopt the beta-prism II fold. PCL subunit binds mannose using a potential bivalent mode instead of the usual trivalent mode, in which carbohydrate-binding site (CBS) I and CBS III adopt the conserved mannose-binding motif of QXDXNXVXY (X is one of any amino acid residues) as observed in other structurally characterized GNA-related lectins, while CBS II adopts a modified motif with residues Gln58 and Asp60, which are critical for mannose-binding, substituted by His58 and Asn60, respectively. As a result, CBS II is unfit for mannose-binding. In the mannoside complexes, ligand bindings only occur at CBS I which provides the specificity for alpha1-3 dimannoside. CBS II and CBS III are cooperatively occupied by a well-ordered sulfate ion, through which the individual dimers are cross-linked to form a unique super-structure of 3(2) helical lattice. Surveying the sequences of GNA-related letins revealed that the modified binding motif of CBS II is widely distributed in the Liliaceae family as an intrinsic structural element. There is evidence that other GNA-related lectins will also adopt the similar super-structure as PCL. Thus PCL structure, unique in ligand-binding mode, may represent a novel type of structure of GNA-related lectins. Comparative analyses indicated that the dimer-based super-structure may play a primary role in the anti-HIV property of PCL.