GGBP proteins and similar proteins

The glucose-galactose binding protein (GGBP) has been resolved crystallographically in an OPEN and a CLOSED (and TWISTED) conformation,

enabling free energy differences to be computed between them (http://www.sciencedirect.com/science/article/pii/S0006349507713097)

Another similar protein, RBP (ribose binding protein) similarly exists in two known resolved forms (OPEN and CLOSED) whose crystal structures

exist.

Mowbray, S. & Cole, L. (1992). The 1.7 A ̊ X-ray structure of the periplasmic ribose receptor of Escherichia coli. J. Mol. Biol. 225, 155–175.

Bjo ̈rkman, A. & Mowbray, S. (1998). Multiple open forms of ribose binding protein trace the path of its conformational change. J. Mol. Biol. 279, 651–664.

I am looking for proteins of any kind that are known to have two forms resolved crystallographically, and suggestions and hints is greatly appreciated!