1c3a
From Proteopedia
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CRYSTAL STRUCTURE OF FLAVOCETIN-A FROM THE HABU SNAKE VENOM, A NOVEL CYCLIC TETRAMER OF C-TYPE LECTIN-LIKE HETERODIMERS
Overview
Snake venom contains a number of the hemostatically active C-type, lectin-like proteins, which affect the interaction between von Willebrand, factor (vWF) and the platelet glycoprotein (GP) Ib or platelet receptor to, inhibit/induce platelet activation. Flavocetin-A (FL-A) is a, high-molecular mass C-type lectin-like protein (149 kDa) isolated from the, habu snake venom. FL-A binds with high affinity to the platelet GP, Ibalpha-subunit and functions as a strong inhibitor of vWF-dependent, platelet aggregation. We have determined the X-ray crystal structure of, FL-A and refined to 2.5 A resolution. This is a first elucidation of a, three-dimensional structure of the platelet GP Ib-binding protein. The, overall structure reveals that the molecule is a novel cyclic tetramer, (alphabeta)(4) made up of four alphabeta-heterodimers related by a, crystallographic 4-fold symmetry. The tetramerization is mediated by an, interchain disulfide bridge between cysteine residues at the C-terminus of, the alpha-subunit and at the N-terminus of the beta-subunit in the, neighboring alphabeta-heterodimer. The high affinity of FL-A for the, platelet GP Ib alpha-subunit could be explained by a cooperative-binding, action through the multiple binding sites of the tetramer.
About this Structure
1C3A is a Protein complex structure of sequences from Trimeresurus flavoviridis. Full crystallographic information is available from OCA.
Reference
Crystal structure of flavocetin-A, a platelet glycoprotein Ib-binding protein, reveals a novel cyclic tetramer of C-type lectin-like heterodimers., Fukuda K, Mizuno H, Atoda H, Morita T, Biochemistry. 2000 Feb 29;39(8):1915-23. PMID:10684640
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