Cleavage of supercoiled double-stranded DNA by several ribosome-inactivating proteins in vitro.
Several ribosome-inactivating proteins (RIPs), such as ricin (including its A-chain), luffin, cinnamomin and camphorin, were found to express enzymatic activity to cleave supercoiled double-stranded DNA. In particular, alpha-sarcin, a RIP with a novel ribonuclease activity, was first proved to have this activity. They convert supercoiled DNA into a nicked circular conformation at low concentrations and further into a linear form at high concentrations: they have no effect on linear DNA. Although intact type II RIPs exhibited no RNA N-glucosidase activity, they were detected to cleave supercoiled DNA. Even if ricin A-chain was treated by boiling, its activity on supercoiled DNA was largely retained.
Ling
J
J
Shanghai Institute of Biochemistry, Academia Sinica, China.
Liu
W Y
WY
Wang
T P
TP
D000818:Animals; D004278:DNA, Superhelical / Q000378:metabolism*; D004926:Escherichia coli / Q000235:genetics; D008099:Liver / Q000378:metabolism*; D046911:Macromolecular Substances; D010957:Plasmids / Q000378:metabolism*; D011506:Proteins / Q000378:metabolism*; D051381:Rats; D012270:Ribosomes / Q000378:metabolism*; D012276:Ricin / Q000378:metabolism*; D013379:Substrate Specificity
D004278:DNA, Superhelical; D046911:Macromolecular Substances; D011506:Proteins; D012276:Ricin