4ch2 | pdb_00004ch2

Low-salt crystal structure of a thrombin-GpIbalpha peptide complex

spinqualitylabelsall models 4ch2, resolution 1.60Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 4ch2 is a 6 chain structure with sequence from Human. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: 0G6, GOL, NA NonStd Res: PTR Related: 4ch8 Activity: Thrombin, with EC number 3.4.21.5 Resources: FirstGlance, OCA, RCSB, PDBsum Disease [THRB_HUMAN] Defects in F2 are the cause of factor II deficiency (FA2D) [MIM:613679]. It is a very rare blood coagulation disorder characterized by mucocutaneous bleeding symptoms. The severity of the bleeding manifestations correlates with blood factor II levels. Genetic variations in F2 may be a cause of susceptibility to ischemic stroke (ISCHSTR) [MIM:601367]; also known as cerebrovascular accident or cerebral infarction. A stroke is an acute neurologic event leading to death of neural tissue of the brain and resulting in loss of motor, sensory and/or cognitive function. Ischemic strokes, resulting from vascular occlusion, is considered to be a highly complex disease consisting of a group of heterogeneous disorders with multiple genetic and environmental risk factors. Defects in F2 are the cause of thrombophilia due to thrombin defect (THPH1) [MIM:188050]. It is a multifactorial disorder of hemostasis characterized by abnormal platelet aggregation in response to various agents and recurrent thrombi formation. Note=A common genetic variation in the 3-prime untranslated region of the prothrombin gene is associated with elevated plasma prothrombin levels and an increased risk of venous thrombosis. Defects in F2 are associated with susceptibility to pregnancy loss, recurrent, type 2 (RPRGL2) [MIM:614390]. A common complication of pregnancy, resulting in spontaneous abortion before the fetus has reached viability. The term includes all miscarriages from the time of conception until 24 weeks of gestation. Recurrent pregnancy loss is defined as 3 or more consecutive spontaneous abortions. [GP1BA_HUMAN] Genetic variations in GP1BA may be a cause of susceptibility to non-arteritic anterior ischemic optic neuropathy (NAION) [MIM:258660]. NAION is an ocular disease due to ischemic injury to the optic nerve. It usually affects the optic disk and leads to visual loss and optic disk swelling of a pallid nature. Visual loss is usually sudden, or over a few days at most and is usually permanent, with some recovery possibly occurring within the first weeks or months. Patients with small disks having smaller or non-existent cups have an anatomical predisposition for non-arteritic anterior ischemic optic neuropathy. As an ischemic episode evolves, the swelling compromises circulation, with a spiral of ischemia resulting in further neuronal damage. Defects in GP1BA are a cause of Bernard-Soulier syndrome (BSS) [MIM:231200]; also known as giant platelet disease (GPD). BSS patients have unusually large platelets and have a clinical bleeding tendency. Defects in GP1BA are the cause of benign mediterranean macrothrombocytopenia (BMM) [MIM:153670]; also known as autosomal dominant benign Bernard-Soulier syndrome. BMM is characterized by mild or no clinical symptoms, normal platelet function, and normal megakaryocyte count. Defects in GP1BA are the cause of pseudo-von Willebrand disease (VWDP) [MIM:177820]. A bleeding disorder is caused by an increased affinity of GP-Ib for soluble vWF resulting in impaired hemostatic function due to the removal of vWF from the circulation. Function [THRB_HUMAN] Thrombin, which cleaves bonds after Arg and Lys, converts fibrinogen to fibrin and activates factors V, VII, VIII, XIII, and, in complex with thrombomodulin, protein C. Functions in blood homeostasis, inflammation and wound healing. [GP1BA_HUMAN] GP-Ib, a surface membrane protein of platelets, participates in the formation of platelet plugs by binding to the A1 domain of vWF, which is already bound to the subendothelium. Publication Abstract from PubMed Activation of platelets by the serine protease thrombin is a critical event in haemostasis. This process involves the binding of thrombin to glycoprotein Ibalpha (GpIbalpha) and cleavage of protease-activated receptors (PARs). The N-terminal extracellular domain of GpIbalpha contains an acidic peptide stretch that has been identified as the main thrombin binding site, and both anion binding exosites of thrombin have been implicated in GpIbalpha binding, but it remains unclear how they are involved. This issue is of critical importance for the mechanism of platelet activation by thrombin. If both exosites bind to GpIbalpha, thrombin could potentially act as a platelet adhesion molecule or receptor dimerisation trigger. Alternatively, if only a single site is involved, GpIbalpha may serve as a cofactor for PAR-1 activation by thrombin. To determine the involvement of thrombin's two exosites in GpIbalpha binding, we employed the complementary methods of mutational analysis, binding studies, X-ray crystallography and NMR spectroscopy. Our results indicate that the peptide corresponding to the C-terminal portion of GpIbalpha and the entire extracellular domain bind exclusively to thrombin's exosite II. The interaction of thrombin with GpIbalpha thus serves to recruit thrombin activity to the platelet surface while leaving exosite I free for PAR-1 recognition. GpIbalpha Interacts Exclusively with Exosite II of Thrombin.,Lechtenberg BC, Freund SM, Huntington JA J Mol Biol. 2013 Dec 5. pii: S0022-2836(13)00738-9. doi:, 10.1016/j.jmb.2013.11.027. PMID:24316004 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Thrombin

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