Substrate-binding domain ChoS of an osmoregulated ABC-type transporter and related proteins; type 2 periplasmic-binding protein fold
Osmoprotectant binding lipoprotein ChoS of Lactococcus lactis is predicted to be involved in uptake of compatible solutes such as choline and glycine betaine, but the relative substrate preference is not known. To counteract the efflux of water, microorganisms accumulate the compatible solutes for a sustained adjustment to high osmolarity surroundings. ChoS 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.
Jiyao W et al.(2023). "The conserved domain database in 2023.",