periplasmic sugar-binding proteins (ThpA and XypA) of ABC-type transport systems
This group includes periplasmic D-threitol-binding protein ThpA and xylitol/L-sorbitol-binding protein XypA, which are part of sugar ABC-type transport systems. Both ThpA and XypA share homology with a family of pentose/hexose sugar-binding proteins of the type 1 periplasmic binding protein superfamily, which consists of two domains connected by a three-stranded hinge.