title: Structural insights into recognition of triple-helical beta-glucans by an insect fungal receptor.
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.
authors.affiliation: Structural Glycobiology Team, Systems Glycobiology Research Group, Chemical Biology Department, RIKEN, Advanced Science Institute, 2-1 Hirosawa Wako, Saitama 351-0198, Japan and.
authors.forename: Mayumi
authors.initials: M
authors.lastname: Kanagawa
authors.affiliation: Structural Glycobiology Team, Systems Glycobiology Research Group, Chemical Biology Department, RIKEN, Advanced Science Institute, 2-1 Hirosawa Wako, Saitama 351-0198, Japan and.
authors.forename: Tadashi
authors.initials: T
authors.lastname: Satoh
authors.affiliation: Structural Glycobiology Team, Systems Glycobiology Research Group, Chemical Biology Department, RIKEN, Advanced Science Institute, 2-1 Hirosawa Wako, Saitama 351-0198, Japan and.
authors.forename: Akemi
authors.initials: A
authors.lastname: Ikeda
authors.affiliation: Laboratory for Immunopharmacology of Microbial Products, School of Pharmacy, Tokyo University of Pharmacy and Life Sciences, 1432-1 Horinouchi, Hachioji, Tokyo 192-0392, Japan.
authors.forename: Yoshiyuki
authors.initials: Y
authors.lastname: Adachi
authors.affiliation: Laboratory for Immunopharmacology of Microbial Products, School of Pharmacy, Tokyo University of Pharmacy and Life Sciences, 1432-1 Horinouchi, Hachioji, Tokyo 192-0392, Japan.
authors.forename: Naohito
authors.initials: N
authors.lastname: Ohno
authors.affiliation: Structural Glycobiology Team, Systems Glycobiology Research Group, Chemical Biology Department, RIKEN, Advanced Science Institute, 2-1 Hirosawa Wako, Saitama 351-0198, Japan and. Electronic address: yyoshiki@riken.jp.
authors.forename: Yoshiki
authors.initials: Y
authors.lastname: Yamaguchi
mesh_terms: D000818:Animals; D002352:Carrier Proteins / Q000737:chemistry*; D019476:Insect Proteins / Q000737:chemistry*; D037102:Lectins / Q000737:chemistry*; D009036:Moths / Q000737:chemistry* / Q000382:microbiology; D017433:Protein Structure, Secondary; D047071:beta-Glucans / Q000737:chemistry*
chemical_list: D002352:Carrier Proteins; D019476:Insect Proteins; D037102:Lectins; D047071:beta-Glucans; C037937:glucan-binding proteins