Structural signatures in EPR3 define a unique class of plant carbohydrate receptors

• Published in: Nature communications Vol. 11; no. 1; pp. 3797 - 8
• Main Authors: Wong, Jaslyn E. M. M., Gysel, Kira, Birkefeldt, Thea G., Vinther, Maria, Muszyński, Artur, Azadi, Parastoo, Laursen, Nick S., Sullivan, John T., Ronson, Clive W., Stougaard, Jens, Andersen, Kasper R.
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 30.07.2020; Nature Publishing Group; Nature Portfolio
• Subjects: 101/1; 631/449/2675; 631/449/2676; 631/45/535; 631/45/72; 64; 82/16; 82/83; Amino Acid Sequence; BASIC BIOLOGICAL SCIENCES; Binding; Carbohydrates; Chemical composition; Exopolysaccharides; Humanities and Social Sciences; Legumes; Lipopolysaccharides - metabolism; Lotus - microbiology; Lotus - physiology; Mesorhizobium - genetics; Mesorhizobium - metabolism; Microbial activity; Microorganisms; multidisciplinary; Nitrogen Fixation - physiology; Plant Proteins - genetics; Plant Proteins - metabolism; Polysaccharides; Protein Folding; Receptors; Root Nodules, Plant - microbiology; Root Nodules, Plant - physiology; Saccharides; Science; Science & Technology - Other Topics; Science (multidisciplinary); Symbiosis; Symbiosis - physiology
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-020-17568-9

Receptor-mediated perception of surface-exposed carbohydrates like lipo- and exo-polysaccharides (EPS) is important for non-self recognition and responses to microbial associated molecular patterns in mammals and plants. In legumes, EPS are monitored and can either block or promote symbiosis with rhizobia depending on their molecular composition. To establish a deeper understanding of receptors involved in EPS recognition, we determined the structure of the Lotus japonicus ( Lotus ) exopolysaccharide receptor 3 (EPR3) ectodomain. EPR3 forms a compact structure built of three putative carbohydrate-binding modules (M1, M2 and LysM3). M1 and M2 have unique βαββ and βαβ folds that have not previously been observed in carbohydrate binding proteins, while LysM3 has a canonical βααβ fold. We demonstrate that this configuration is a structural signature for a ubiquitous class of receptors in the plant kingdom. We show that EPR3 is promiscuous, suggesting that plants can monitor complex microbial communities though this class of receptors. Exopolysaccharides (EPS) are perceived by legumes and regulate symbiosis with rhizobia. Here the authors describe the structure of the Lotus EPS receptor, EPR3 and show that it has atypical βαββ and βαβ folds that represent a structural signature for a unique class of EPS receptors in the plant kingdom.