Crystal structure of the plant symporter STP10 illuminates sugar uptake mechanism in monosaccharide transporter superfamily

• Published in: Nature communications Vol. 10; no. 1; p. 407
• Main Authors: Paulsen, Peter Aasted, Custódio, Tânia F., Pedersen, Bjørn Panyella
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 24.01.2019; Nature Publishing Group; Nature Portfolio
• Subjects: 631/449/1659; 631/449/2653; 631/45/72/1204; 631/535/1266; Animals; Arabidopsis - genetics; Arabidopsis - metabolism; Arabidopsis Proteins - genetics; Arabidopsis Proteins - metabolism; Biological Transport - genetics; Biological Transport - physiology; Bonding strength; Chemical bonds; Deformation; Dicarboxylic acids; Dimerization; Glucose - metabolism; Humanities and Social Sciences; Ion Transport - physiology; Metals; Models, Molecular; Monosaccharide Transport Proteins - genetics; Monosaccharide Transport Proteins - metabolism; Monosaccharides - metabolism; multidisciplinary; Protein Conformation; Recognition; Science; Science (multidisciplinary); Sugars - metabolism; Symporters - genetics; Symporters - metabolism; Xenopus; Zinc
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-018-08176-9

Plants are dependent on controlled sugar uptake for correct organ development and sugar storage, and apoplastic sugar depletion is a defense strategy against microbial infections like rust and mildew. Uptake of glucose and other monosaccharides is mediated by Sugar Transport Proteins, proton-coupled symporters from the Monosaccharide Transporter (MST) superfamily. We present the 2.4 Å structure of Arabidopsis thaliana high affinity sugar transport protein, STP10, with glucose bound. The structure explains high affinity sugar recognition and suggests a proton donor/acceptor pair that links sugar transport to proton translocation. It contains a Lid domain, conserved in all STPs, that locks the mobile transmembrane domains through a disulfide bridge, and creates a protected environment which allows efficient coupling of the proton gradient to drive sugar uptake. The STP10 structure illuminates fundamental principles of sugar transport in the MST superfamily with implications for both plant antimicrobial defense, organ development and sugar storage. Plants are dependent on controlled sugar uptake via Monosaccharide Transporters, such as STP10, for correct organ development, sugar accumulation in fruits and microbial defense. Here authors present the crystal structure of STP10 bound to glucose which sheds light on the fundamental principles of sugar transport in the plant-unique MST superfamily.