title: Structural and functional analysis of BB0689 from Borrelia burgdorferi, a member of the bacterial CAP superfamily.
abstract: Spirochete Borrelia burgdorferi is the causative agent of Lyme disease and is transmitted from infected Ixodes ticks to a mammalian host after a tick bite. The outer surface protein BB0689 from B. burgdorferi is up-regulated when the tick feeds, which indicates a potential role for BB0689 in Lyme disease pathogenesis. We have determined the crystal structure of BB0689, which revealed that the protein belongs to the CAP superfamily. Though the CAP domain is widespread in all three cellular domains of life, thus far the CAP domain has been studied only in eukaryotes, in which it is usually linked to certain other domains to form a multi-domain protein and is associated with the mammalian reproductive tract, the plant response to pathogens, venom allergens from insects and reptiles, and the growth of human brain tumors. Though the exact function of the isolated CAP domain remains ambiguous, several functions, including the binding of cholesterol, lipids and heparan sulfate, have been recently attributed to different CAP domain proteins. In this study, the bacterial CAP domain structure was analyzed and compared with the previously solved crystal structures of representative CAPs, and the function of BB0689 was examined. To determine the potential function of BB0689 and ascertain whether the functions that have been attributed to the CAP domain proteins are conserved, the binding of previously reported CAP domain interaction partners was analyzed, and the results suggested that BB0689 has a unique function that is yet to be discovered.
authors.affiliation: Latvian Institute of Organic Synthesis, Aizkraukles 21, LV-1006 Riga, Latvia; Latvian Biomedical Research and Study Centre, Ratsupites 1 k-1, LV-1067 Riga, Latvia; Riga Stradins University, Dzirciema 16, LV-1007 Riga, Latvia. Electronic address: kalvis@biomed.lu.lv.
authors.forename: Kalvis
authors.initials: K
authors.lastname: Brangulis
authors.affiliation: Latvian Institute of Organic Synthesis, Aizkraukles 21, LV-1006 Riga, Latvia.
authors.forename: Kristaps
authors.initials: K
authors.lastname: Jaudzems
authors.affiliation: Latvian Biomedical Research and Study Centre, Ratsupites 1 k-1, LV-1067 Riga, Latvia.
authors.forename: Ivars
authors.initials: I
authors.lastname: Petrovskis
authors.affiliation: Latvian Biomedical Research and Study Centre, Ratsupites 1 k-1, LV-1067 Riga, Latvia.
authors.forename: Inara
authors.initials: I
authors.lastname: Akopjana
authors.affiliation: Latvian Biomedical Research and Study Centre, Ratsupites 1 k-1, LV-1067 Riga, Latvia.
authors.forename: Andris
authors.initials: A
authors.lastname: Kazaks
authors.affiliation: Latvian Biomedical Research and Study Centre, Ratsupites 1 k-1, LV-1067 Riga, Latvia; University of Latvia, Kronvalda bulv. 4, LV-1586 Riga, Latvia.
authors.forename: Kaspars
authors.initials: K
authors.lastname: Tars
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001425:Bacterial Outer Membrane Proteins / Q000378:metabolism / Q000648:ultrastructure*; D001665:Binding Sites; D025065:Borrelia burgdorferi / Q000472:pathogenicity*; D002784:Cholesterol / Q000378:metabolism; D003001:Cloning, Molecular; D018360:Crystallography, X-Ray; D005227:Fatty Acids / Q000378:metabolism; D018884:Ixodes / Q000382:microbiology; D008193:Lyme Disease / Q000473:pathology*; D008958:Models, Molecular; D008969:Molecular Sequence Data; D011485:Protein Binding; D017434:Protein Structure, Tertiary
chemical_list: D001425:Bacterial Outer Membrane Proteins; D005227:Fatty Acids; D002784:Cholesterol
keywords: CAP domain; Ixodes ticks; Lyme disease; Outer surface proteins