Mapping of the Primary Binding Site of Measles Virus to Its Receptor CD46 (original) (raw)
Related papers
Protein Science, 2008
The two terminal complement control protein (CCP) modules of the CD46 glycoprotein mediate measles virus binding. Three-dimensional models for these two domains were derived based on the NMR structures of two CCP modules of factor H. Both CD46 CCP modules are about 35 8, long, and form a five-stranded antiparallel P-barrel structure. Monte Carlo simulations, sampling the backbone torsion angles of the linker peptide and selecting possible orientations on the basis of minimal solvent-exposed hydrophobic area, were used to predict the orientation of CCP-I relative to CCP-11. We tested this procedure successfully for factor H. For CD46, three clusters of structures differing in the tilt angle of the two domains were obtained. To test these models, we mutagenized the CCP modules. Four proteins, two without an oligosaccharide chain and two with mutated short amino acid segments, reached the cell surface efficiently. Only the protein without the CCP-I oligosaccharide chain maintained binding to the viral attachment protein hemagglutinin. These results are consistent with one of our models and suggest that the viral hemagglutinin does not bind at the membrane-distal tip of CD46, but near the concave CCP-1-11 interface region.
Structure of the measles virus hemagglutinin bound to the CD46 receptor
Nature Structural & Molecular Biology, 2009
The binding site in MV-H for nectin-4 also overlaps extensively with those of the other two receptors. Finally, a hydrophobic pocket centered in the b4-b5 groove is involved in binding to all three identified measles virus receptors, representing a potential target for antiviral drugs.
Journal of Biological Chemistry, 2002
Measles virus (MV) is a human pathogen using two distinct cell surface receptors for entry into host cells. We present here a comparative analysis for binding of the MV receptors CD46 and SLAM to the measles virus hemagglutinin protein (MVH, Edmonston strain). Soluble monomeric and dimeric MVH variants were prepared in mammalian cells and their conformation assessed using a panel of monoclonal antibodies. The two receptor molecules specifically bound to the MVH protein with distinct binding modes. The association rate (k a) for SLAM binding to MVH was very low (ϳ3000 M ؊1 s ؊1), about 20 times lower that the k a determined for CD46 binding. However, SLAM bound tighter to the virus protein than CD46, as revealed by a 5-fold lower dissociation rate (k d , ϳ1.5 ؋ 10 ؊3 s ؊1). These data suggest that the SLAM receptor binds to a less accessible and more hydrophobic surface on MVH than the CD46 receptor, as illustrated in a binding model. Despite the differences in kinetics, receptor competition binding experiments revealed that they recognize overlapping sites in MVH. Indeed, a panel of anti-MVH monoclonal antibodies equally inhibited binding of both receptor molecules. The similar immune reactivity of the two receptor binding sites suggests that the shift in receptor usage by MV may not be driven by immune responses.
… and Crystallization …, 2009
The measles virus (MV) hemagglutinin (MV-H) mediates the attachment of MV particles to cell-surface receptors for entry into host cells. MV uses two receptors for attachment to host cells: the complement-control protein CD46 and the signalling lymphocyte activation molecule (SLAM). The MV-H glycoprotein from an Edmonston MV variant and the MV-binding fragment of the CD46 receptor were overproduced in mammalian cells and used to crystallize an MV-H–CD46 complex. Well diffracting crystals containing two complexes in the asymmetric unit were obtained and the structure of the complex was solved by the molecular-replacement method.
Measles Virus Glycoprotein Complex Assembly, Receptor Attachment, and Cell Entry
Current Topics in Microbiology and Immunology
Measles virus (MV) enters cells by membrane fusion at the cell surface at neutral pH. Two glycoproteins mediate this process: the hemagglutinin (H) and fusion (F) proteins. The H-protein binds to receptors, while the F-protein mediates fusion of the viral and cellular membranes. H naturally interacts with at least three different receptors. The wild-type virus primarily uses the signaling lymphocyte activation molecule (SLAM, CD150) expressed on certain lymphatic cells, while the vaccine strain has gained the ability to also use the ubiquitous membrane cofactor protein (MCP, CD46), a regulator of complement activation. Additionally, MV infects polarized epithelial cells through an unidentified receptor (EpR). The footprints of the three receptors on H have been characterized, and the focus of research is shifting to the characterization of receptor-specific conformational changes that occur in the H-protein dimer and how these are transmitted to the F-protein trimer. It was also shown that MV attachment and cell entry can be readily targeted to designated receptors by adding specificity determinants to the H-protein.
Measles Virus and C3 Binding Sites are Distinct on Membrane Cofactor Protein (CD46
Proceedings of The National Academy of Sciences, 1995
The human complement regulatory protein membrane cofactor protein (CD46) is the cellular receptor for measles virus (MV), whereas decay accelerating factor (DAF; CD55), a structurally similar complement regulatory protein, does not bind MV. To characterize the interaction between MV and CD46, mutants of the CD46 protein and hybrid molecules between CD46 and DAF were tested for their ability to act as MV receptors. The transmembrane domain and cytoplasmic tail of CD46 were not required for receptor function as cells expressing the CD46 extracellular domain linked to the glycosyl-phosphatidylinositol tail of DAF were rendered susceptible to MV infection. Chimeric proteins exchanging the four extracellular short consensus repeat (SCR) domains between CD46 and DAF indicated that only molecules with both SCR1 and SCR2 from CD46 allowed a productive MV infection. Further, monoclonal antibodies (mAbs) against SCR1 or SCR2 of CD46 blocked MV infection, whereas a mAb against SCR3 and SCR4 did not. The latter mAb blocks C3b/C4b
Journal of Virology, 2004
expressed only in immune cells or through the ubiquitously expressed regulator of complement activation, CD46. To identify residues on the attachment protein hemagglutinin (H) essential for fusion support through either receptor, we devised a strategy based on analysis of morbillivirus H-protein sequences, iterative cycles of mutant protein production followed by receptor-based functional assays, and a novel MV H three-dimensional model. This model uses the Newcastle disease virus hemagglutinin-neuraminidase protein structure as a template. We identified seven amino acids important for SLAM-and nine for CD46 (Vero cell receptor)induced fusion. The MV H three-dimensional model suggests (i) that SLAM-and CD46-relevant residues are located in contiguous areas in propeller -sheets 5 and 4, respectively; (ii) that two clusters of SLAM-relevant residues exist and that they are accessible for receptor contact; and (iii) that several CD46-relevant amino acids may be shielded from direct receptor contacts. It appears likely that certain residues support receptorspecific H-protein conformational changes. To verify the importance of the H residues identified with the cell-cell fusion assays for virus entry into cells, we transferred the relevant mutations into genomic MV cDNAs. Indeed, we were able to recover recombinant viruses, and we showed that these replicate selectively in cells expressing SLAM or CD46. Selectively receptor-blind viruses will be used to study MV pathogenesis and may have applications for the production of novel vaccines and therapeutics.
Journal of Virology, 2008
Measles is one of the most contagious human infectious diseases and remains a major cause of childhood morbidity and mortality worldwide. The signaling lymphocyte activation molecule (SLAM), also called CD150, is a cellular receptor for measles virus (MV), presumably accounting for its tropism for immune cells and its immunosuppressive properties. On the other hand, pathological studies have shown that MV also infects epithelial cells at a later stage of infection, although its mechanism has so far been unknown. In this study, we show that wild-type MV can infect and produce syncytia in human polarized epithelial cell lines independently of SLAM and CD46 (a receptor for the vaccine strains of MV). Progeny viral particles are released exclusively from the apical surface of these polarized epithelial cell lines. We have also identified amino acid residues on the MV attachment protein that are likely to interact with a putative receptor on epithelial cells. All of these residues have aromatic side chains and may form a receptor-binding pocket located in a different position from the putative SLAM-and CD46-binding sites on the MV attachment protein. Thus, our results indicate that MV has an intrinsic ability to infect both polarized epithelial and immune cells by using distinctive receptorbinding sites on the attachment protein corresponding to each of their respective receptors. The ability of MV to infect polarized epithelial cells and its exclusive release from the apical surface may facilitate its efficient transmission via aerosol droplets, resulting in its highly contagious nature.
European Journal of Biochemistry, 2003
Neutralizing and protective monoclonal antibodies (mAbs) were used to fine-map the highly conserved hemagglutinin noose epitope (H379-410, HNE) of the measles virus. Short peptides mimicking this epitope were previously shown to induce virus-neutralizing antibodies J. Gen. Virol. 81, 729-735]. The epitope contains three cysteine residues, two of which (Cys386 and Cys394) form a disulfide bridge critical for antibody binding. Substitution and truncation analogues revealed four residues critical for binding (Lys387, Gly388, Gln391 and Glu395) and suggested the binding motif X 7 C[KR]GX[AINQ]QX 2 CEX 5 for three distinct protective mAbs. This motif was found in more than 90% of the wild-type viruses. An independent molecular model of the core epitope predicted an amphiphilic loop displaying a remarkably stable and rigid loop conformation. The three hydrophilic contact residues Lys387, Gln391 and Glu395 pointed on the virus towards the solvent-exposed side of the planar loop and the permissive hydrophobic residues Ile390, Ala392 and Leu393 towards the solvent-hidden side of the loop, precluding antibody binding. The high affinity (K d ¼ 7.60 nM) of the mAb BH216 for the peptide suggests a high structural resemblance of the peptide with the natural epitope and indicates that most interactions with the protein are also contributed by the peptide. Improved peptides designed on the basis of these findings induced sera that crossreacted with the native measles virus hemagglutinin protein, providing important information about a lead structure for the design of more stable antigens of a synthetic or recombinant subunit vaccine.