5AVA: Crystal Structure Of Pha-e Lectin In Complex With Bisected Glycan

Citation:
Abstract
Glycans normally exist as a dynamic equilibrium of several conformations. A fundamental question concerns how such molecules bind lectins despite disadvantageous entropic loss upon binding. Bisected glycan, a glycan possessing bisecting N-acetylglucosamine (GlcNAc), is potentially a good model for investigating conformational dynamics and glycan-lectin interactions, owing to the unique ability of this sugar residue to alter conformer populations and thus modulate the biological activities. Here we analyzed bisected glycan in complex with two unrelated lectins, Calsepa and PHA-E. The crystal structures of the two complexes show a conspicuous flipped back glycan structure (designated 'back-fold' conformation), and solution NMR analysis also provides evidence of 'back-fold' glycan structure. Indeed, statistical conformational analysis of available bisected and non-bisected glycan structures suggests that bisecting GlcNAc restricts the conformations of branched structures. Restriction of glycan flexibility by certain sugar residues may be more common than previously thought and impinges on the mechanism of glycoform-dependent biological functions.
PDB ID: 5AVADownload
MMDB ID: 138505
PDB Deposition Date: 2015/6/12
Updated in MMDB: 2016/06
Experimental Method:
x-ray diffraction
Resolution: 3  Å
Source Organism:
Similar Structures:
Biological Unit for 5AVA: tetrameric; determined by author and by software (PISA)
Molecular Components in 5AVA
Label Count Molecule
Proteins (4 molecules)
4
Erythroagglutinin
Molecule annotation
Chemicals (34 molecules)
1
4
2
4
3
14
4
4
5
4
6
4
* Click molecule labels to explore molecular sequence information.

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