Mutational analysis of the putative receptor-binding domain of Moloney murine leukemia virus glycoprotein gp70

The entry of Moloney murine leukemia virus (MoMuLV) to murine cells is medi ated by the binding of its envelope glycoprotein gp70 to its receptor, the cationic amino acid transporter MCAT-1. The binding property of the envelop e protein lies mainly in the N-terminal half of the protein. To identify es sential residues involved in the binding of gp70 to its receptor, we have m utated amino acids within the putative receptor-binding domain of MoMuLV gp 70. Changes in the residues P94 and W100 resulted in lower vira I titers in comparison to the wild-type virions. Single, double, or triple point mutat ions involving the residue W100 make the envelope protein severely defectiv e in binding to its receptor. Binding studies and cell fusion experiments w ith murine XC cells suggested that the residue W100 might play an important role in the process of infection by making contact between gp70 and its re ceptor. (C) 2000 Academic Press.