Liang Feng, Stanford University, Structure and mechanism of SemiSWEET sugar transporter

Sugars serve as the principal energy source, basic building material and important signal molecules in both animals and plants. Their distribution throughout the organism is controlled by sugar transport across the membrane, which is mediated by sugar transporters. The recently discovered SWEET family proteins are monosaccharide and disaccharide transporters and play crucial roles in pollen nutrition, seed development, nectar sweetening as well as pathogen susceptibility. SWEET homologs in prokaryotes, called SemiSWEET, are among the smallest natural transporters. We have solved high-resolution structures of SemiSWEETs in different conformational states, which reveal the architecture of this transporter family and provide structural basis to understand their transport mechanism.