Selection and characterization of ricin toxin A-chain mutations in Saccharomyces cerevisiae.
A DNA sequence encoding the A chain of ricin toxin (RTA) from the castor bean plant, Ricinus communis, was placed under GAL1 promoter control and transformed into Saccharomyces cerevisiae. Induction of expression of RTA was lethal. This lethality was the basis for a selection of mutations in RTA which inactivated the toxin. A number of mutant alleles which encoded cross-reactive material were sequenced. Eight of the first nine mutant RTAs studied showed single-amino-acid changes involving residues located in the proposed active-site cleft.
Frankel
A
A
Department of Medicine, Duke University, Durham, North Carolina 27710.
Schlossman
D
D
Welsh
P
P
Hertler
A
A
Withers
D
D
Johnston
S
S
D000595:Amino Acid Sequence; D003001:Cloning, Molecular; D003062:Codon / Q000235:genetics; D004247:DNA / Q000235:genetics; D005804:Genes, Lethal; D007120:Immunochemistry; D008969:Molecular Sequence Data; D009154:Mutation; D037121:Plant Lectins; D010940:Plant Proteins / Q000235:genetics; D010947:Plants, Toxic; D010957:Plasmids; D012313:RNA / Q000235:genetics; D012276:Ricin / Q000235:genetics* / Q000276:immunology; D012278:Ricinus / Q000235:genetics; D012441:Saccharomyces cerevisiae / Q000235:genetics
D003062:Codon; D037121:Plant Lectins; D010940:Plant Proteins; D012313:RNA; D004247:DNA; D012276:Ricin