Structural insights into recognition of triple-helical beta-glucans by an insect fungal receptor
Kanagawa, M., Satoh, T., Ikeda, A., Adachi, Y., Ohno, N., Yamaguchi, Y.(2011) J Biol Chem 286: 29158-29165
- PubMed: 21697086 
- DOI: https://doi.org/10.1074/jbc.M111.256701
- Primary Citation of Related Structures:  
3AQX, 3AQY, 3AQZ - PubMed Abstract: 
The innate ability to detect pathogens is achieved by pattern recognition receptors, which recognize non-self-components such as β1,3-glucan. β1,3-Glucans form a triple-helical structure stabilized by interchain hydrogen bonds. β1,3-Glucan recognition protein (βGRP)/gram-negative bacteria-binding protein 3 (GNBP3), one of the pattern recognition receptors, binds to long, structured β1,3-glucan to initiate innate immune response. However, binding details and how specificity is achieved in such receptors remain important unresolved issues. We solved the crystal structures of the N-terminal β1,3-glucan recognition domain of βGRP/GNBP3 (βGRP-N) in complex with the β1,3-linked glucose hexamer, laminarihexaose. In the crystals, three structured laminarihexaoses simultaneously interact through six glucose residues (two from each chain) with one βGRP-N. The spatial arrangement of the laminarihexaoses bound to βGRP-N is almost identical to that of a β1,3-glucan triple-helical structure. Therefore, our crystallographic structures together with site-directed mutagenesis data provide a structural basis for the unique recognition by such receptors of the triple-helical structure of β1,3-glucan.
Organizational Affiliation: 
Structural Glycobiology Team, Systems Glycobiology Research Group, Chemical Biology Department, RIKEN, Advanced Science Institute, 2-1 Hirosawa Wako, Saitama 351-0198, Japan and.