Anticoagulation factor I, a snaclec (snake C-type lectin) from Agkistrodon acutus venom binds to FIX as well as FX: Ca2+ induced binding data

作者：Zhang Yan; Xu Xiaolong^*; Shen Dengke; Song Jiajia; Guo Mingchun; Yan Xincheng

来源：Toxicon, 2012, 59(7-8): 718-723.

DOI：10.1016/j.toxicon.2012.03.006

• Agkistrodon acutuss
• ACF I
• Snaclec
• Ca2+
• Factor IX

Anticoagulation factor I (ACF I), a snake C-type lectin (snaclec) from the venom of Agkistrodon acutus binds specifically with activated factor X (FXa) in a Ca2+-dependent manner and prolongs the blood-clotting time in vitro. In this study, the inhibition of the coagulation pathway by ACF I was measured in vivo by activated partial thromboplastin time and prothrombin time assays and the binding of ACF I to factor IX (FIX) was investigated by native PAGE and surface plasmon resonance. The results indicate that ACF I inhibits both intrinsic and extrinsic coagulation pathways, but does not inhibit thrombin activity. ACF I also binds FIX in a Ca2+-dependent manner and their maximal binding occurs at 0.25 mM Ca2+. ACF I has a higher binding-affinity to FIX than to FX. Ca2+ is required to maintain in vivo function of FIX Gla domain for its recognition of ACF I. However, Ca2+ at high concentrations (>0.25 mM) inhibits the binding of ACF I to FIX. Ca2+ functions as a switch for the binding between ACF I and FIX. The results suggest that the binding of ACF I with FIX may play a dominant role in the anticoagulation activity of ACF I in vivo.

• 出版日期2012-6-1
• 单位中国科学技术大学