Identification of a CG/LH binding site in two strains of Mycobacterium vaccae

We have previously reported the presence of a chorionic gonadotropin-like (CG-like) protein in the bacterium Xanthomonas maltophilia (X. maltophilia). We have also shown that X. maltophilia possesses a unique binding site for the native ligand and hCG, but not for human luteinizing hormone (hLH), and that binding of the native ligand or hCG to the receptor causes changes in the growth rates of culturing X. maltophilia. In this study we have characterized a CG/LH binding site in two strains of Mycobacterium vaccae. The binding site is specific for hCG and hLH, and Scatchard analysis reveals a biphasic, high affinity binding pattern. This is the second identified bacterial species to possess a CG-specific binding site.