A novel platelet glycoprotein Ib-binding protein with human platelet aggregation-inhibiting activity from Trimeresurus jerdonii venom.
Platelet glycoprotein Ib (GPIb) is a primary adhesion receptor and involved in platelet-related disorders. However, it is difficult to study GPIb-specific platelet stimulation using physiological ligands in vivo. GPIb-binding snake C-type lectins (snaclecs) are useful tools for exploring GPIb in vitro because they act on platelets differently. In the present study, a novel GPIb-binding snaclec, named jerdonibitin, was purified, molecular cloned and characterized from Trimeresurus jerdonii venom. On SDS-polyacrylamide gel electrophoresis, it showed a single band with an apparent molecular weight of 25 kDa under non-reducing conditions and two distinct bands with apparent molecular weights of 15 kDa (α-subunit) and 13 kDa (β-subunit) under reducing conditions. The cDNA sequences of each subunit of jerdonibitin were identified and both deduced amino acid sequences were confirmed by N-terminal protein sequencing and trypsin-digested peptide mass fingerprinting of MALDI-TOF. Sequence alignment showed that jerdonibitin is a snaclec and has sequence similarity with TSV-GPIb-BP (a GPIb-inhibitory snaclec). Jerdonibitin dose-dependently inhibited platelet aggregation induced by ristocetin or low-dose thrombin, but not by high-dose thrombin. The GPIbα was detected by affinity chromatography on jerdonibitin. In vivo, jerdonibitin also dose-dependently induced thrombocytopenia of mice and platelet counts remained at very low level after 18 h intravenous injection. In summary, a novel GPIb-inhibitory snaclec was molecular cloned and characterized, which might provide insights into investigation of how GPIb-inhibitory snaclecs work and development of new antiplatelet agents.
Key Laboratory of Animal Models and Human Disease Mechanisms, Kunming Institute of Zoology, The Chinese Academy of Sciences, Kunming 650223, Yunnan, China.
ZhongMing
Z
Chen
JianBo
J
Wu
Yong
Y
Zhang
XingWang
X
Yang
GuoYu
G
Yu
ShaoWen
S
Zhu
WenHui
W
Lee
QiuMing
Q
Lu
Yun
Y
Zhang
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D003001:Cloning, Molecular; D003435:Crotalid Venoms / Q000737:chemistry*; D016172:DNA Fingerprinting; D004591:Electrophoresis, Polyacrylamide Gel; D006801:Humans; D037181:Lectins, C-Type / Q000032:analysis / Q000235:genetics / Q000302:isolation & purification* / Q000378:metabolism*; D008969:Molecular Sequence Data; D019038:Platelet Glycoprotein GPIb-IX Complex / Q000378:metabolism*; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
D003435:Crotalid Venoms; D037181:Lectins, C-Type; D019038:Platelet Glycoprotein GPIb-IX Complex; C029748:Trimeresurus venoms