Extended Data Figure 8. Conservation of SWEET and key residues in the transport pathway of OsSWEET2b.

a, Conservation surface mapping of OsSWEET2b, which is coloured according to the degree of conservation of the surface residues of 527 analysed SWEET sequences. b, The cut-away view of OsSWEET2b shows the degree of the conservation of residues lining the transport route. Two clusters with higher conservation are labelled and correspond with the presumptive sugar binding site (I) and the intrafacial gate (II). c, Ribbon representation of OsSWEET2b with selected residues in the transport pathway are shown as sticks. Extrafacial gate residues are coloured in yellow, substrate binding pocket residues in green, and intrafacial hinge residues in cyan. d, Amino acids flanking the critical prolines in the intrafacial gate are also essential for AtSWEET1 activity. Alanine substitution of residues immediately above and below the conserved prolines that form the intrafacial gate in AtSWEET1 reduce the transport of glucose. Growth of the EBY4000 strain is unaffected in maltose. These results suggest that mutations in residues flanking the intrafacial gate have a similar effect as mutations of the conserved prolines.