Extended Data Fig. 6: Structural and functional analysis of the OsSPS3–FBN5 complex.
From: Structural insights into the molecular mechanisms of OsFBN5-induced OsSPS3 catalysis
a, Structural superposition of the apo-OsFBN5 (salmon) with the GGSPP-bound OsSPS3–FBN5 complex, with one of the OsFBN5 units colored khaki. b, Structural alignment of the OsFBN5 β-barrel channel with the OsSPS3 catalytic pockets. c, Comparison of the apo-OsSPS3–FBN5 (gray) and GGSPP-bound OsSPS3–FBN5 (blue) cryo-EM structures reveals a flip in the side chain conformation of Phe237. d, Michaelis–Menten curves of OsSPS3(R201A) in the absence (triangles) and presence (circles) of OsFBN5 with GGPP as the allylic substrate and IPP as the counter substrate applied at a fixed concentration. The data were calculated from three independent experiments (n = 3, shown as the mean ± s.d.). e, Structural superposition of the ZOL/IPP bound OsSPS3 (pink) with the GGSPP-bound OsSPS3–FBN5 complex (sky blue). f, Superposition of ZOL/IPP-bound OsSPS3 with the GGSPP-bound OsSPS3–FBN5 complex showing conformational changes in the dimerization helices G and H. The arrows indicate the deflection angle. g, Structural alignment of active and inactive monomers of ZOL/IPP-bound OsSPS3 with the OsSPS3 monomer in GGSPP-bound OsSPS3–FBN5. h, Molecular dynamics (MD) simulations reveal that the stable binding of the substrates GGPP/IPP is mediated by critical residues (Arg188 and Arg189) in both OsSPS3 monomers of the OsSPS3–FBN5 complex.
