Mapping of the Primary Binding Site of Measles Virus to Its Receptor CD46

• Published in: The Journal of biological chemistry Vol. 272; no. 35; pp. 22072 - 22079
• Main Authors: Buchholz, Christian J., Koller, Daniel, Devaux, Patricia, Mumenthaler, Christian, Schneider-Schaulies, Jürgen, Braun, Werner, Gerlier, Denis, Cattaneo, Roberto
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 29.08.1997; American Society for Biochemistry and Molecular Biology
• Subjects: Amino Acid Sequence; Animals; Antibodies, Monoclonal - metabolism; Antigens, CD - chemistry; Binding Sites; Complement Inactivator Proteins - chemistry; Epitope Mapping; Hemagglutinins - metabolism; Life Sciences; Measles virus - chemistry; Membrane Cofactor Protein; Membrane Glycoproteins - chemistry; Mice; Mice, Inbred BALB C; Microbiology and Parasitology; Models, Molecular; Molecular Sequence Data; Protein Binding; Protein Structure, Tertiary; Receptors, Virus - chemistry; Virology
• ISSN: 0021-9258; 1083-351X
• DOI: 10.1074/jbc.272.35.22072

The measles virus (MV) hemagglutinin binds to the complement control protein (CCP) CD46 primarily through the two external modules, CCP-I and -II. To define the residues involved in binding, 40 amino acids predicted to be solvent-exposed on the CCP-I-II module surface were changed to either alanine or serine. Altered proteins were expressed on the cell surface, and their abilities to bind purified MV particles, a soluble form of hemagglutinin (sH) and nine CD46-specific antibodies competing to different levels with sH attachment, were measured. All proteins retained, at least in part, MV and sH binding, but some completely lost binding to certain antibodies. Amino acids essential for binding of antibodies weakly or moderately competing with sH attachment are situated in the membrane-distal tip of CCP-I, whereas residues involved in binding of strongly sH competing antibodies cluster in the center of CCP-I (Arg-25, Asp-27) or in CCP-II (Arg-69, Asp-70). Both clusters face the same side of CCP-I-II and map close to amino acid exchanges impairing sH binding (E11A, R29A, P39A, and D70A) or MV binding (D70A and E84A) and to a six-amino acid loop, previously shown to be necessary for sH binding.