The substrate-binding domain of the 32-kilodalton lipoprotein (Tp32) from Treponema pallidum binds L-methionine; the type 2 periplasmic-binding protein fold
This group includes the lipoprotein Tp32, a periplasmic component of a methionine uptake transporter system, and its closely related homologs. The Tp32 has both structural and sequential homology to the MetQ family of substrate-binding protein, and thus it 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.
Jiyao W et al.(2023). "The conserved domain database in 2023.",