Lysine-dependent multipoint binding of the Borrelia burgdorferi virulence factor outer surface protein E to the C terminus of factor H.
Serum resistance, an important virulence determinant of Borrelia burgdorferi sensu lato strains belonging to the Borrelia afzelii and B. burgdorferi sensu stricto genotypes, is related to binding of the complement inhibitor factor H to the spirochete surface protein outer surface protein E (OspE) and its homologues. In this study, we show that the C-terminal short consensus repeats 18-20 of both human and mouse factor H bind to OspE. Analogously, factor H-related protein 1, a distinct plasma protein with three short consensus repeat domains homologous to those in factor H, bound to OspE. Deleting 15-aa residues (region V) from the C terminus of the OspE paralog P21 (a 20.7-kDa OspE-paralogous surface lipoprotein in the B. burgdorferi sensu stricto 297 strain) abolished factor H binding. However, C-terminal peptides from OspE, P21, or OspEF-related protein P alone and the C-terminal deletion mutants of P21 inhibited factor H binding to OspE only partially when compared with full-length P21 or its N-terminal mutant. Alanine substitution of amino acids in peptides from the key binding regions of the OspE family indicated that several lysine residues are required for factor H binding. Thus, the borrelial OspE family proteins bind the C inhibitor factor H via multiple sites in a lysine-dependent manner. The C-terminal site V (Ala(151)-Lys(166)) is necessary, but not sufficient, for factor H binding in both rodents and humans. Identification of the necessary binding sites forms a basis for the development of vaccines that block the factor H-OspE interaction and thereby promote the killing of Borreliae.
Alitalo
Antti
A
Department of Bacteriology and Immunology, Haartman Institute and Helsinki University Central Hospital, University of Helsinki, Helsinki, Finland.
Meri
Taru
T
Chen
Tong
T
Lankinen
Hilkka
H
Cheng
Zhu-Zhu
ZZ
Jokiranta
T Sakari
TS
Seppälä
Ilkka J T
IJ
Lahdenne
Pekka
P
Hefty
P Scott
PS
Akins
Darrin R
DR
Meri
Seppo
S
D000595:Amino Acid Sequence; D000818:Animals; D000942:Antigens, Bacterial / Q000235:genetics / Q000378:metabolism*; D001425:Bacterial Outer Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D001798:Blood Proteins / Q000378:metabolism; D025065:Borrelia burgdorferi / Q000235:genetics / Q000378:metabolism* / Q000472:pathogenicity; D017242:Complement Factor H / Q000037:antagonists & inhibitors / Q000378:metabolism*; D016384:Consensus Sequence; D006493:Heparin / Q000494:pharmacology; D006801:Humans; D008074:Lipoproteins / Q000235:genetics / Q000378:metabolism*; D008239:Lysine / Q000378:metabolism*; D051379:Mice; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D010446:Peptide Fragments / Q000235:genetics / Q000378:metabolism*; D011485:Protein Binding / Q000187:drug effects / Q000235:genetics / Q000276:immunology; D017434:Protein Structure, Tertiary; D020449:Repetitive Sequences, Amino Acid; D017384:Sequence Deletion; D020349:Surface Plasmon Resonance; D037521:Virulence Factors / Q000235:genetics / Q000378:metabolism*
D000942:Antigens, Bacterial; D001425:Bacterial Outer Membrane Proteins; D001426:Bacterial Proteins; D001798:Blood Proteins; C493495:CFH protein, human; D008074:Lipoproteins; C084998:OspE protein, Borrelia burgdorferi; D010446:Peptide Fragments; D037521:Virulence Factors; C100631:factor H-related protein 1; C067935:VMP21 antigen, Borrelia; D017242:Complement Factor H; D006493:Heparin; D008239:Lysine