FIGURE 3.

(A) Sequence alignment between GlpT and OxlT protein families around helix 8 and 9. The sequences used are a selection from the most closely related transporter families such as UhpT. The sequence codes are from the Swiss-Prot or TREMBL database. Positions colored in red and green indicate negatively and positively charged residues, respectively. Positions colored in green are hydrophobic residues at sites where a hydrophobic residue is usually present. Positions colored in magenta represent nonhydrophobic, but conserved residues. Underlined letters indicate residues that are highly conserved in general. (B) Revised secondary structure model for OxlT showing the presence of two positively charged residues in the transmembrane region.