1c3a
From Proteopedia
CRYSTAL STRUCTURE OF FLAVOCETIN-A FROM THE HABU SNAKE VENOM, A NOVEL CYCLIC TETRAMER OF C-TYPE LECTIN-LIKE HETERODIMERS
Structural highlights
Function[SLAA_PROFL] Strong platelet aggregation inhibitor. Binds specifically to platelet glycoprotein Ibalpha (GP1BA) with high affinity and inhibits vWF-dependent platelet aggregation (PubMed:7599152). Has also been observed to induce small agglutinates in washed platelets by binding to GPIb (PubMed:10688335).[1] [2] [SLAB_PROFL] Strong platelet aggregation inhibitor. Binds specifically to platelet glycoprotein Ibalpha (GP1BA) with high affinity and inhibits vWF-dependent platelet aggregation (PubMed:7599152). Has also been observed to induce small agglutinates in washed platelets by binding to GPIb (PubMed:10688335).[3] [4] Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedSnake 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. 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[5] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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