Structure-function relationship of trichosanthin.
Trichosanthin (TCS), a 27 kDa ribosome inactivating protein extracted from the root tuber of Trichosanthes plant, was subjected to limited chymotrypsin digestion and three peptide fragments designated TCS-F1 72-247, TCS-F2 100-247, and TCS-F3 133-247 were generated. The RNA-N-glycosidase and cytotoxic activities of the TCS fragments were compared with that of inact TCS. TCS-F1 and TCS-F2 were biologically active, while TCS-F3 was completely inactive. Dose-dependent studies showed that TCS-F1 and TCS-F2 were less potent in their trophoblast cytotoxicity than intact TCS, however, full biological effect could still be obtained with a higher dosage. Based on the known three-dimensional structure of TCS, we postulate that the putative active site of TCS is located at amino acid residues 110 to 174.
Ke
Y B
YB
Shanghai Institute of Cell Biology, Academia Sinica, China.
Chen
J K
JK
Nie
H L
HL
He
X H
XH
Ke
X Y
XY
Wang
Y H
YH
D002918:Chymotrypsin / Q000737:chemistry; D004591:Electrophoresis, Polyacrylamide Gel; D007525:Isoelectric Focusing; D010446:Peptide Fragments / Q000737:chemistry; D010449:Peptide Mapping; D013329:Structure-Activity Relationship; D015978:Trichosanthin / Q000737:chemistry* / Q000494:pharmacology*
D010446:Peptide Fragments; D015978:Trichosanthin; D002918:Chymotrypsin