QLS motif in transmembrane helix VII of the glucose transporter family interacts with the C-1 position of D-glucose and is involved in substrate selection at the exofacial binding site

A study was conducted on the role of QLS motif in transmembrane helix VII of the glucose transporter family. The findings indicate that the QLS motif in helix VII functions as a molecular filter that dictates the ability of GLUTs 1, 3 and 4 to transport glucose. Moreover, this region of helix VII plays a key role in substrate recognition at the exofacial substrate binding site by interaction with the C-1 position of the incoming sugar molecule.