FIG 10.

Schematic presentation of the E. faecalis transport systems catalyzing the uptake of maltose, maltotriose, maltotetraose, and the maltotriose linkage isomers panose and isopanose. While maltose and maltotriose are primarily transported by the PTS permease MalT, maltotetraose and longer maltooligosaccharides, as well as panose and isopanose, are taken up by the ABC transporter MdxEFG-MsmX. When substrates or arrows are in gray, this indicates that they are transported with low efficiency. This applies for the transport of maltotriose by the ABC transporter MdxEFG-MsmX and the uptake of maltose by a yet-unknown transport protein.