2.A.1.1.12
Glucose uniporter, Glut3 (also transports dehydro-ascorbate; Maulén et al., 2003). Down-regulated in the brains of Alzheimer's disease patients (Liu et al., 2008b).  The structure of the human orthologue with D-glucose bound was solved at 1.5 Å resolution in the outward occluded conformation (Deng et al. 2015).  Sugars are predominantly coordinated by polar residues in the C-terminal domain. The conformational transition from the outward-open to the outward-occluded states entails a prominent local rearrangement of the extracellular part of  TMS 7. Comparison of the outward-facing GLUT3 structures with inward-open GLUT1 provides insight into the alternating access cycle for GLUTs, whereby the C-terminal domain provides the primary substrate-binding site and the N-terminal domain undergoes rigid-body rotation with respect to the C-terminal domain (Deng et al. 2015). Glut3 is involved in several disease states in humans (Lechermeier et al. 2019). Resveratrol and soy isoflavones alone and in combination improve the learning and memory of aging rats. The mechanism may be related to up-regulating the expression of GLUT1 and GLUT3 genes and proteins in the hippocampus (Zhang et al. 2020).