Crystal structure of a bacterial homologue of glucose transporters GLUT1–4
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 informationfor GLUT1–4 or their homologues remains largely unknown. Nieng Yan group of Tsinghua University reported three related crystal structures of XylE, anEscherichia coli homologue of GLUT1–4, in complex with D-xylose, D-glucose and 6-bromo-6-deoxy-D-glucose,the latter two were determined using MX Beamline at Shanghai Synchrotron Radiation Facility. The structure consists of a typical major facilitator superfamily fold of 12transmembrane segments and a unique intracellular four-helix domain. XylE was captured in an outward-facing, partlyoccludedconformation.Mostof the important amino acids responsible for recognitionof D-xylose or D-glucose are invariantin GLUT1–4, suggesting functional andmechanistic conservations. Structure-based modelling of GLUT1–4 allows mappingand interpretation of disease-related mutations. The structural and biochemical information reported here constitutes animportant framework for mechanistic understanding of glucose transporters and sugar porters in general.
The structure of XylE