Transmembrane subunit (TM) of Escherichia coli AraH and related proteins. E. coli AraH is the TM of a Periplasmic Binding Protein (PBP)-dependent ATP-Binding Cassette (ABC) transporter involved in the uptake of the monosaccharide arabinose. This group also contains E. coli RbsC, AlsC, and MglC, which are TMs of other monosaccharide transporters, the ribose transporter, the D-allose transporter and the galactose transporter, respectively. The D-allose transporter may also be involved in low affinity ribose transport. These transporters generally bind type 1 PBPs. PBP-dependent ABC transporters consist of a PBP, two TMs, and two cytoplasmic ABCs, and are mainly involved in importing solutes from the environment. The solute is captured by the PBP, which delivers it to a gated translocation pathway formed by the two TMs. The two ABCs bind and hydrolyze ATP and drive the transport reaction. Proteins in this subgroup have a single TM which homodimerizes to generate the transmembrane pore.