G15SecL05Tpc3

Outer Surface Protein B (Osp-B) of the Borrelia burgdorferi Spirochete Bacterium (Title)Outer Surface Protein B (Osp-B) of the Borrelia burgdorferi Spirochete Bacterium (Title)

spinqualitylabelsall models Fab H6831, Light and Heavy Chains Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image

spinqualitylabelsall models Osp-B Structure, Bound Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image

is a primary outer-surface lipoprotein molecule found in the Lyme disease spirochete Borrelia burgdorferi, a molecule essential for the survival of the bacterium. Since its primary function is to serve both as a site of antibody recognition and as the microvillar attachment to the Ixodes scapularis midgut, it is constitutively expressed.

Significance in Lyme Disease and Bind BriefingSignificance in Lyme Disease and Bind Briefing

Lyme disease is a bacterial infectious disease of the skin, joints, nervous system and heart dominantly caused by the spirochete Borrelia burgdorferi, transmitted to humans via the bite of the deer tick Ixodes scapularis (Becker, 2005). The importance of antibodies in controlling such spirochaetal infections was underscored by the discovery of two particular antibodies with distinctive bactericidal properties: the monoclonal antibodies CB2 and H6831 (Connoly, Benach). When directed against the C-terminus of the outer-surface protein Osp-B, these fragments are bactericidal even in the absence of complements or phagocytes (Sadziene, 1994). The formation of the OspB-CB2 and OspB-H6831 complexes were dependent upon a single lysine residue in Osp-B, Lys 253 (GREEN LINK THAT), for binding and thus leading to lysis of the outer membrane of the spirochete; the structural changes that result culminate into molecular instability and protease susceptibility that eventually lead to said lysis, though the exact physiological consequences of these changes are not yet fully sequenced nor understood (Connoly, Benach). These antibodies demonstrate enormous selective pressure; growth of Borrelia burgdorferi spirochetes in their presence generated escape mutants that lacked the critical Lys 253 amino acid on Osp-B for antibody binding, and were thus less infectious in experimental mouse models and in vitro experimental assays (Connoly, Benach).

Related StructuresRelated Structures

• Crystal structure of the C-terminal fragment
• OspB-H6831 Complex
• CB2

LinksLinks

• Lyme Disease CDC Lyme Disease Webpage
• Borrelia burgdorferi
• Ixodes Dammini

Notes and Literature ReferencesNotes and Literature References

• 1. Becker, M., Bunikis, J., Lade, B.D, Dunn, J.J., Barbour, A.G., Lawson, C.L. “Structural Investigation of Borrelia burgdorferi OspB, a BactericidalFab Target” The Journal of Biological Chemistry; Vol. 280, No.17, issue of April 29, pp. 17363- 17370, 2005
• 2. Connolly, S.E., Benach, J.L. “The Versatile Roles of Antibodies in Borrelia Infections” Nature Reviews: Microbiology, Volume 3, May 2005, pp. 411-420
• 3. LaRocca, T.J., Benach, J.L. 2008 “The Important and Diverse Roles of Antibodies in the Host Response to Borrelia Infections” Specialization and Complementation of Humoral Immune Responses to in Infection. Current Topics in Microbiology and Immunology 319