The structure of D-galactose-binding protein at 4.1 A resolution looks like L-arabinose-binding protein

The structure of D-galactose-binding protein, a receptor for both high affinity active transport system and chemotaxis in Escherichia coli, has been solved at 4.1 A resolution using three heavy atom derivatives. The molecule is ellipsoidal with dimensions of about 65 X 35 X 35 A. The overall shape of the molecule and the indication that the molecule consists of two domains separated by a cleft are reminiscent of the structure of L-arabinose-binding protein.