title: Substitution in the murine nectin1 receptor of a single conserved amino acid at a position distal from the herpes simplex virus gD binding site confers high-affinity binding to gD.
abstract: By analogy with its human nectin1 counterpart, murine nectin1 serves as a cellular receptor for the entry of herpes simplex virus (HSV) into murine cells. HSV entry mediated by either receptor is dependent on the viral glycoprotein D (gD). Whereas human nectin1 binds gD at high affinity and in a saturable manner, murine nectin1 binds gD in a barely detectable fashion, depending on the sensitivity of the assay. The immunoglobulin type V domain of murine nectin differs from its human counterpart in 11 amino acids. To identify the key residues responsible for the high-affinity binding of gD to human nectin1, we replaced each of the 11 divergent amino acids with the human counterparts singly or in groups in an incremental manner. Replacement in murine nectin1 of six amino acids that lie within the gD binding region of human nectin1 (previously mapped to residues 64 to 94, likely the CC'C" surface) increased the gD binding activity to a limited extent. In contrast, the single P138L substitution, which lies distal from the gD binding site, markedly increased gD binding. This substitution, when coupled with downstream substitutions, exerted the greatest effect. Three-dimensional modeling of the nectin1 V domain suggested that P138 in murine nectin1 might decrease the stability of the V domain by reducing the size of beta-strand G. The results support the notion that the overall structure of V nectin1 plays a pivotal role in its ability to bind HSV gD.
authors: Department of Experimental Pathology, Section on Microbiology and Virology, University of Bologna, Bologna, Italy.
authors: Laura
authors: L
authors: Menotti
authors: Rita
authors: R
authors: Casadio
authors: Carlo
authors: C
authors: Bertucci
authors: Marc
authors: M
authors: Lopez
authors: Gabriella
authors: G
authors: Campadelli-Fiume
mesh_terms: D000595:Amino Acid Sequence; D019943:Amino Acid Substitution; D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology; D001665:Binding Sites; D015815:Cell Adhesion Molecules / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D002460:Cell Line; D003198:Computer Simulation; D017124:Conserved Sequence; D006224:Cricetinae; D018985:Epitopes, B-Lymphocyte / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D018259:Herpesvirus 1, Human / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D051379:Mice; D008958:Models, Molecular; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D000075983:Nectins; D017434:Protein Structure, Tertiary; D011991:Receptors, Virus / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D017386:Sequence Homology, Amino Acid; D014759:Viral Envelope Proteins / Q000235:genetics / Q000378:metabolism*
chemical_list: D000911:Antibodies, Monoclonal; D015815:Cell Adhesion Molecules; D018985:Epitopes, B-Lymphocyte; C000619010:NECTIN1 protein, human; C000619015:Nectin1 protein, mouse; D000075983:Nectins; D011991:Receptors, Virus; D014759:Viral Envelope Proteins; C039447:glycoprotein D, Human herpesvirus 1