The periplasmic substrate-binding domain of the membrane-associated lipoprotein-9 GmpC; contains the type 2 periplasmic-binding protein fold
This group includes the membrane-associated lipoprotein-9 from Staphylococcus aureus that binds the dipeptide glycylmethionine (GlyMet). The lipoprotein-9 has both structural and sequential homology to the MetQ family of substrate-binding protein. The GlyMet binding protein belongs to the type 2 periplasmic binding fold protein superfamily (PBP2). The PBP2 proteins are typically comprised of two globular subdomains connected by a flexible hinge and bind their ligand in the cleft between these domains in a manner resembling a Venus flytrap. The majority of PBP2 proteins function in the uptake of small soluble substrates in eubacteria and archaea.