Antiviral Agents/pharmacology; Eosinophil-Derived Neurotoxin/chemistry; Eosinophil-Derived Neurotoxin/pharmacology; Mutagenesis, Insertional/genetics; Amino Acid Sequence; Amino Acid Substitution; Antiviral Agents/chemistry; Arginine/chemistry; Catalytic Domain; Cell Line, Tumor; Enzyme Activation; Enzyme Assays; Eosinophil Cationic Protein/chemistry; Eosinophil Cationic Protein/genetics; Eosinophil-Derived Neurotoxin/genetics; Escherichia coli/chemistry; Escherichia coli/genetics; Glutamine/chemistry; Host-Pathogen Interactions; Humans; Molecular Sequence Data; Mutagenesis, Site-Directed; Proline/chemistry; RNA, Viral/chemistry; RNA, Viral/genetics; Recombinant Proteins/chemistry; Recombinant Proteins/genetics; Recombinant Proteins/pharmacology; Respiratory Syncytial Viruses/drug effects; Respiratory Syncytial Viruses/genetics; Respiratory Syncytial Viruses/pathogenicity; Ribonuclease, Pancreatic/chemistry; Ribonuclease, Pancreatic/genetics; Sequence Alignment