Mg(II)-induced binding of factor IX-binding protein from the venom of Agkistrodon Halys Pallas with factor Xa.
Factor IX-binding protein (AHP IX-bp), a Ca2+- and Zn2+-binding protein from the venom of Agkistrodon Halys Pallas was reported to bind specifically with factor IX in a Zn2+-dependent manner. Here we have purified AHP IX-bp by a simple two-step of chromatography procedure and found that AHP IX-bp also binds factor Xa (FXa) with high binding-affinity in a Mg2+-dependent manner. Although Mg2+ ions have a significantly low binding-affinity for apo-AHP IX-bp as determined by isothermal titration calorimetry, they can induce the binding of apo-AHP IX-bp with FXa even in the absence of Ca2+ as determined by native PAGE and surface plasmon resonance. Mg2+ ions are required to maintain in vivo function of FX Gla domain for its recognition of AHP IX-bp. Both Ca2+ and Zn2+ ions fail to induce the binding between apo-AHP IX-bp and FXa. The abundant Mg2+ ions in blood play an important role in the anticoagulation of AHP IX-bp.
Wu
Hao
H
Department of Chemistry, University of Science and Technology of China, No. 96, Jinzhai Road, Hefei 230026, PR China.
Xu
Xiaolong
X
Zhang
Liyun
L
Shen
Dengke
D
Peng
Lili
L
Zhang
Yan
Y
Song
Jiajia
J
D017836:Agkistrodon / Q000378:metabolism*; D000818:Animals; D000925:Anticoagulants / Q000378:metabolism* / Q000494:pharmacology; D002118:Calcium / Q000494:pharmacology; D002151:Calorimetry; D004591:Electrophoresis, Polyacrylamide Gel; D015951:Factor Xa / Q000378:metabolism*; D007525:Isoelectric Focusing; D008274:Magnesium / Q000494:pharmacology*; D011485:Protein Binding / Q000187:drug effects; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D020349:Surface Plasmon Resonance; D014757:Viper Venoms / Q000737:chemistry* / Q000378:metabolism / Q000494:pharmacology; D015032:Zinc / Q000494:pharmacology
C478742:AHP IX-bp protein, Agkistrodon halys; D000925:Anticoagulants; D014757:Viper Venoms; D015951:Factor Xa; D008274:Magnesium; D015032:Zinc; D002118:Calcium