previous studies with mutant tso23 ( iii ) and vaccinia virus m-gene expression vectors revealed that the temperature-sensitive phenotype is due to a mutation leading to substitution of phenylalanine for leucine at amino acid iii , whereas loss of the major antigenic determinant ( epitope 1 ) of the mutant m protein results from the substitution of glutamic acid for the wild-type amino acid glycine at position 21 ( y .
C0002520
amino acid
C0061472
glutamic acid