title: Site-directed mutagenesis at amino terminus of recombinant ricin A chain.
abstract: Successful immunotoxin therapy may depend upon reduction of the size of the components in order to decrease antigenicity and rate of clearance. In initial attempts to modify the A chain of ricin by deletion analyses within a prokaryotic expression system, coding sequences were modified by the insertion of unique restriction endonuclease sites and by the removal of 22 codons near the 5' terminus. The work presented here examines the expression, solubility, and activity of these mutant proteins and demonstrates that while amino acid residues may be altered in this region, the deletion of residues 19 through 40 yields an insoluble and inactive toxin molecule.
authors.affiliation: Department of Biochemistry and Molecular Biology, University of Florida, Gainesville.
authors.forename: J L
authors.initials: JL
authors.lastname: Bradley
authors.forename: M
authors.initials: M
authors.lastname: Piatak
authors.forename: J A
authors.initials: JA
authors.lastname: Lane
authors.forename: P M
authors.initials: PM
authors.lastname: McGuire
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D004262:DNA Restriction Enzymes; D004591:Electrophoresis, Polyacrylamide Gel; D008969:Molecular Sequence Data; D009154:Mutation; D010957:Plasmids; D011994:Recombinant Proteins; D012276:Ricin / Q000235:genetics*; D012995:Solubility; D013010:Sonication; D013329:Structure-Activity Relationship
chemical_list: D011994:Recombinant Proteins; D012276:Ricin; D004262:DNA Restriction Enzymes