Disclosed are recombinant plant cells, plant cell parts, plant parts and
transgenic plants containing a DNA molecule comprising a sequence encoding a Pokeweed
Antiviral Protein (PAP) II protein. PAP II proteins include full length, wild-type
PAP II and substantially nontoxic mutants or analogs including fragments thereof
truncated at the C-terminus and other PAP II proteins having an intact catalytic
active site amino acid residue E172 but that also have at least one amino acid
substitution or deletion, and possess anti-viral and/or anti-fungal activity. DNA
molecules comprising sequences encoding the mutants or analogs, as well as the
isolated and purified PAP II proteins per se, are also disclosed. Methods of identifying
nontoxic PAP II mutants are further disclosed.
Transgenic plants that produce a PAP II protein exhibit anti-viral and/or
anti-fungal activity. Virtually all flowering plants are included. Seed derived
from the transgenic plants are also provided.