Fig. 2

Structural modelling of OsSIP1 and OsSIP2 proteins. (A, B) Membrane topology of OsSIP1 and OsSIP2 The transmembrane helices are numbered in Roman numerals, and the loop regions are indicated (LA-LE). Residues in the NPA motif and the ar/R constriction (R1, R2, R3, R4) are highlighted in green and red respectfully. Residues shaded in olive green represent the putative phosphorylation residues. (C, D) The ar/R region in the 3D structures of OsSIP1 and OsSIP2 predicted by homology modelling using the SWISS-MODEL server and depicted using PyMol. The four residues of the region are shown as sticks for their side chains. The colored spheres represent the pore at the constriction. (E) A superimposition of the predicted structures of OsSIP1 and OsSIP2 showing only the ar/R constrictions. See Methods for details