title: Crystal structure of the platelet activator convulxin, a disulfide-linked alpha4beta4 cyclic tetramer from the venom of Crotalus durissus terrificus.
abstract: Convulxin (CVX), a C-type lectin, isolated from the venom of the South American rattlesnake Crotalus durissus terrificus, causes cardiovascular and respiratory disturbances and is a potent platelet activator which binds to platelet glycoprotein GPVI. The structure of CVX has been solved at 2.4A resolution to a crystallographic residual of 18.6% (R(free)=26.4%). CVX is a disulfide linked heterodimer consisting of homologous alpha and beta chains. The heterodimers are additionally linked by disulfide bridges to form cyclic alpha(4)beta(4)heterotetramers. These domains exhibit significant homology to the carbohydrate-binding domains of C-type lectins, to the factor IX-binding protein (IX-bp), and to flavocetin-A (Fl-A) but sequence and structural differences are observed in both the domains in the putative Ca(2+)and carbohydrate binding regions.
authors.affiliation: Department of Physics, IBILCE/UNESP, R. Cristovão Colombo 2265, CEP 15054-000, São Josédo Rio Preto-SP, Brazil.
authors.forename: M T
authors.initials: MT
authors.lastname: Murakami
authors.forename: S P
authors.initials: SP
authors.lastname: Zela
authors.forename: L M
authors.initials: LM
authors.lastname: Gava
authors.forename: S
authors.initials: S
authors.lastname: Michelan-Duarte
authors.forename: A C O
authors.initials: AC
authors.lastname: Cintra
authors.forename: R K
authors.initials: RK
authors.lastname: Arni
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001665:Binding Sites; D002118:Calcium / Q000378:metabolism; D003435:Crotalid Venoms / Q000737:chemistry* / Q000378:metabolism; D017839:Crotalus; D018360:Crystallography, X-Ray; D004220:Disulfides / Q000737:chemistry; D037181:Lectins, C-Type / Q000737:chemistry* / Q000378:metabolism; D008958:Models, Molecular; D008969:Molecular Sequence Data; D020836:Protein Structure, Quaternary; D021122:Protein Subunits; D016415:Sequence Alignment
chemical_list: D003435:Crotalid Venoms; D004220:Disulfides; D037181:Lectins, C-Type; D021122:Protein Subunits; C028890:convulxin; D002118:Calcium