Structural studies of chromosomally encoded outer surface lipoprotein BB0158 from Borrelia burgdorferi sensu stricto

Lyme disease, or also known as Lyme borreliosis, is caused by the spirochetes belonging to the Borrelia burgdorferi sensu lato complex, which can enter the human body following the bite of an infected tick. Many membrane lipid-bound proteins, also known as lipoproteins, are located on the surface of B. burgdorferi sensu lato and play a crucial role in the spirochete to interact with its environment, whether in ticks or mammals. Since the spirochete needs to perform various tasks, such as resisting the host's immune system or spreading throughout the organism, it is not surprising that numerous surface proteins have been found to be essential for B. burgdorferi sensu lato complex bacteria in causing Lyme disease. In this study, we have determined (at 2.4 Å resolution) and characterized the 3D structure of BB0158, one of the few chromosomally encoded outer surface proteins from B. burgdorferi sensu stricto. BB0158 belongs to the paralogous gene family 44 (PFam44), consisting of four other members (BB0159, BBA04, BBE09 and BBK52). The characterization of BB0158, which appears to form a domain-swapped dimer, in conjunction with the characterization of the corresponding PFam44 members, certainly contribute to our understanding of B. burgdorferi sensu stricto proteins.