4GBY: The Structure Of The Mfs (Major Facilitator Superfamily) Proton:xylose Symporter Xyle Bound To D-Xylose

Glucose transporters are essential for metabolism of glucose in cells of diverse organisms from microbes to humans, exemplified by the disease-related human proteins GLUT1, 2, 3 and 4. Despite rigorous efforts, the structural information for GLUT1-4 or their homologues remains largely unknown. Here we report three related crystal structures of XylE, an Escherichia coli homologue of GLUT1-4, in complex with d-xylose, d-glucose and 6-bromo-6-deoxy-D-glucose, at resolutions of 2.8, 2.9 and 2.6 A, respectively. The structure consists of a typical major facilitator superfamily fold of 12 transmembrane segments and a unique intracellular four-helix domain. XylE was captured in an outward-facing, partly occluded conformation. Most of the important amino acids responsible for recognition of D-xylose or d-glucose are invariant in GLUT1-4, suggesting functional and mechanistic conservations. Structure-based modelling of GLUT1-4 allows mapping and interpretation of disease-related mutations. The structural and biochemical information reported here constitutes an important framework for mechanistic understanding of glucose transporters and sugar porters in general.
PDB ID: 4GBYDownload
MMDB ID: 104092
PDB Deposition Date: 2012/7/28
Updated in MMDB: 2012/11
Experimental Method:
x-ray diffraction
Resolution: 2.81  Å
Source Organism:
Similar Structures:
Biological Unit for 4GBY: monomeric; determined by author and by software (PISA)
Molecular Components in 4GBY
Label Count Molecule
Protein (1 molecule)
D-xylose-proton Symporter(Gene symbol: xylE)
Molecule annotation
Chemicals (5 molecules)
* Click molecule labels to explore molecular sequence information.

Citing MMDB