title: Deciphering the interface between a CD40 receptor and borrelial ligand OspA.
abstract: Neuroborreliosis is serious sequelae of Lyme borreliosis. Neuroinvasion is largely relied on successful translocation of Borrelia across the blood-brain barrier. Adherence of Borrelia to brain microvascular endothelial cell (BMEC) seems to be critical for translocation. Here we unfold the interface between OspA and CD40 molecules, major ligand and receptor, that are involved in adhesion of Borrelia to BMECs. We found that a region between Asn127 and Asp205 of OspA forms the CD40-receptor binding site. This region encompasses human umbilical vein endothelial cell (HUVEC) binding domain and contains a potential ligand-binding pocket lined by three amino acid residues: Arg139, Glu160 and Lys189. Disruption of this pocket (by truncation of the HUVEC binding domain) caused complete abrogation of its ability to bind CD40. To identify the amino acid residues within the HUVEC binding domain involved in the CD40 binding, site-directed mutagenesis and binding assays were performed. Results showed that Asp149, Phe165, Ala172, Val186 and Leu192 might form interface with CD40 molecule. Other side of the interface was also identified with the help of a ligand-binding assay with OspA and truncated CD40 fragments. Results exposed that cysteine rich domain 2 (CRD2) of CD40 might be the site for OspA binding. Precise knowledge of the molecular basis of the ligand-receptor interactions is essential in order to understand mechanisms of pathogenesis and could help in the development of novel therapeutics and vaccines.
authors.affiliation: Laboratory of Biomedical Microbiology and Immunology, Department of Microbiology and Immunology, The University of Veterinary Medicine and Pharmacy in Kosice, 041 81 Kosice, Slovakia.
authors.forename: Patrik
authors.initials: P
authors.lastname: Mlynarcik
authors.affiliation: Laboratory of Biomedical Microbiology and Immunology, Department of Microbiology and Immunology, The University of Veterinary Medicine and Pharmacy in Kosice, 041 81 Kosice, Slovakia.
authors.forename: Lucia
authors.initials: L
authors.lastname: Pulzova
authors.affiliation: Laboratory of Biomedical Microbiology and Immunology, Department of Microbiology and Immunology, The University of Veterinary Medicine and Pharmacy in Kosice, 041 81 Kosice, Slovakia.
authors.forename: Elena
authors.initials: E
authors.lastname: Bencurova
authors.affiliation: Institute of Neuroimmunology of Slovak Academy of Sciences, 845 10 Bratislava, Slovakia.
authors.forename: Andrej
authors.initials: A
authors.lastname: Kovac
authors.affiliation: Animal Breeding and Genomics Group, Department of Genetics, University of Cordoba, 140 71 Cordoba, Spain.
authors.forename: Miguel A
authors.initials: MA
authors.lastname: Dominguez
authors.affiliation: Laboratory of Biomedical Microbiology and Immunology, Department of Microbiology and Immunology, The University of Veterinary Medicine and Pharmacy in Kosice, 041 81 Kosice, Slovakia.
authors.forename: Stanislav
authors.initials: S
authors.lastname: Hresko
authors.affiliation: Laboratory of Biomedical Microbiology and Immunology, Department of Microbiology and Immunology, The University of Veterinary Medicine and Pharmacy in Kosice, 041 81 Kosice, Slovakia; Institute of Neuroimmunology of Slovak Academy of Sciences, 845 10 Bratislava, Slovakia. Electronic address: mangeshbhide@me.com.
authors.forename: Mangesh R
authors.initials: MR
authors.lastname: Bhide
mesh_terms: D000595:Amino Acid Sequence; D019943:Amino Acid Substitution; D000818:Animals; D000954:Antigens, Surface / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D001425:Bacterial Outer Membrane Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D001428:Bacterial Vaccines / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D001665:Binding Sites; D001898:Borrelia; D019013:CD40 Antigens / Q000235:genetics / Q000378:metabolism*; D002460:Cell Line; D015870:Gene Expression; D014644:Genetic Variation; D006801:Humans; D008024:Ligands; D008074:Lipoproteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D008193:Lyme Disease; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009154:Mutation; D011485:Protein Binding; D011487:Protein Conformation; D054730:Protein Interaction Domains and Motifs; D051381:Rats; D011994:Recombinant Proteins
chemical_list: D000954:Antigens, Surface; D001425:Bacterial Outer Membrane Proteins; D001428:Bacterial Vaccines; D019013:CD40 Antigens; D008024:Ligands; D008074:Lipoproteins; C072045:OspA protein; D011994:Recombinant Proteins
keywords: Adhesion; CD40; Ligand–receptor interaction; Neuroborreliosis; OspA