FIGURE 1.
Sequence alignment of vSGLT, PutP, and LeuT. The alignment is based on a structure-structure alignment using Matt (32), followed by manual adjustments to remove gaps in helical regions. TM boundaries for LeuT and vSGLT are defined according to those of Yamshita et al. (1) and Faham et al. (4), respectively. The unwound regions in the TM1/1′ and TM6/6′ are underlined. Substrate-binding site residues identified in the crystal structures of LeuT and vSGLT (PDB codes 2A65 and 3DH4, respectively) are highlighted with cyan and red, respectively; the S1 residues of LeuT are from Ref. 52, and the Se residues of vSGLT are defined as having closest heavy atom distance <4.5 Å to the substrate galactose.