Characterization and molecular cloning of dabocetin, a potent antiplatelet C-type lectin-like protein from Daboia russellii siamensis venom.
A novel C-type lectin-like protein, dabocetin, was purified from Daboia russellii siamensis venom. On SDS-polyacrylamide gel electrophoresis, it showed a single band with an apparent molecular weight of 28 kDa and two distinct bands with the apparent molecular weights of 15.0 kDa and 14.5 kDa under non-reducing and reducing conditions, respectively. cDNA clones containing the coding sequences for dabocetin alpha and beta subunits were isolated and sequenced. The deduced protein sequences of both subunits were confirmed by N-terminal amino acid sequencing and trypsin-digested peptide mass fingerprinting. Dabocetin did not induce platelet aggregation in platelet-rich plasma. It also had little effect on the platelet aggregation induced by ADP, TMVA or stejnulxin. Whereas, dabocetin inhibited ristocetin-induced platelet agglutination in platelet-rich plasma in a dose-dependent manner with an IC50 value of 0.35 microM. Flow cytometry analysis showed that dabocetin significantly inhibited mAb SZ2 binding to platelet membrane glycoprotein Ib alpha, indicating that platelet membrane glycoprotein Ib is involved in the inhibitory effect of dabocetin on ristocetin-induced platelet agglutination.
Zhong
Shu-Rong
SR
Department of Animal Toxinology, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming 650223, China.
Jin
Yang
Y
Wu
Jian-Bo
JB
Chen
Run-Qiang
RQ
Jia
Yong-Hong
YH
Wang
Wan-Yu
WY
Xiong
Yu-Liang
YL
Zhang
Yun
Y
D000244:Adenosine Diphosphate / Q000494:pharmacology; D000595:Amino Acid Sequence; D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology / Q000378:metabolism; D001483:Base Sequence; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000235:genetics; D004591:Electrophoresis, Polyacrylamide Gel; D005434:Flow Cytometry; D020128:Inhibitory Concentration 50; D037181:Lectins, C-Type / Q000037:antagonists & inhibitors* / Q000235:genetics / Q000302:isolation & purification; D008969:Molecular Sequence Data; D008970:Molecular Weight; D010974:Platelet Aggregation / Q000187:drug effects*; D010975:Platelet Aggregation Inhibitors / Q000494:pharmacology*; D019038:Platelet Glycoprotein GPIb-IX Complex / Q000037:antagonists & inhibitors; D012310:Ristocetin / Q000494:pharmacology; D014757:Viper Venoms / Q000737:chemistry* / Q000235:genetics / Q000494:pharmacology; D017819:Viperidae
D000911:Antibodies, Monoclonal; D018076:DNA, Complementary; D037181:Lectins, C-Type; D010975:Platelet Aggregation Inhibitors; D019038:Platelet Glycoprotein GPIb-IX Complex; D014757:Viper Venoms; C509501:dabocetin protein, Daboia russellii siamensis; D012310:Ristocetin; D000244:Adenosine Diphosphate