2.A.123.3.1
SemiSWEET half putative sugar transporter of 97 aas and 3 TMSs with an N-terminal amphipathic α-helix.  The protein occurs as a tight homodimer with the translocation channel between the two monomers.  The 3-d structure is known at 1.7 Å resolution revealing the occluded conformation (Xu et al. 2014). The outward open state of the Leptospira biflexa SemiSWEET (2.a.123.2.6) has been solved at 2.4 Å resolution (Xu et al. 2014).  The presence of these two states argues in favor of a carrier (rocker switch) mechanism rather than a channel-type mechanism (Xu et al. 2014).