Structural characterization of EMS16, an antagonist of collagen receptor (GPIa/IIa) from the venom of Echis multisquamatus.
Snake venoms contain a number of hemostatically active C-type lectin-like proteins (CLPs), which affect the blood coagulation system, endothelial cells, and platelets. CLPs have broad similarities in structure and possess distinct biological functions. EMS16, a CLP from Echis multisquamatus venom, which is a potent and selective inhibitor of the collagen receptor, glycoprotein Ia/IIa (integrin alpha2beta1), has been used in the present study to examine structure-function relationships in venom CLPs by X-ray crystallography. The structure of EMS16, determined at a resolution of 1.9 A, revealed a heterodimer involved with domain swapping of the central loop as observed in the structures of other CLPs. A part of the glycan was observed and identified as N-acetyl-D-glucosamine (GlcNAc) in the electron density map at Asn21 of subunit B, an expected glycosylation site. EMS16 had a unique, positively charged electrostatic potential patch on the concave surface that may qualify as a site for interaction with the I-domain of the glycoprotein Ia/IIa.
Department of Biochemistry, National Institute of Agrobiological Sciences, 2-1-2 Kannondai, Tsukuba, Ibaraki 305-8602, Japan.
Katsunori
K
Horii
Daiju
D
Okuda
Takashi
T
Morita
Hiroshi
H
Mizuno
D000595:Amino Acid Sequence; D000818:Animals; D037181:Lectins, C-Type / Q000737:chemistry*; D008958:Models, Molecular; D008969:Molecular Sequence Data; D011487:Protein Conformation; D038981:Receptors, Collagen / Q000037:antagonists & inhibitors*; D017386:Sequence Homology, Amino Acid; D014757:Viper Venoms / Q000737:chemistry*; D017819:Viperidae
C412704:EMS16 lectin, Echis multisquamtus; D037181:Lectins, C-Type; D038981:Receptors, Collagen; D014757:Viper Venoms