1jvq

Crystal structure at 2.6A of the ternary complex between antithrombin, a P14-P8 reactive loop peptide, and an exogenous tetrapeptide

spinqualitylabelsall models 1jvq, resolution 2.60Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 1jvq is a 4 chain structure with sequence from Homo sapiens. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 2.6Å Ligands: ACE, NAG, NDG, NH2 Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Disease ANT3_HUMAN Defects in SERPINC1 are the cause of antithrombin III deficiency (AT3D) [MIM:613118. AT3D is an important risk factor for hereditary thrombophilia, a hemostatic disorder characterized by a tendency to recurrent thrombosis. AT3D is classified into 4 types. Type I: characterized by a 50% decrease in antigenic and functional levels. Type II: has defects affecting the thrombin-binding domain. Type III: alteration of the heparin-binding domain. Plasma AT-III antigen levels are normal in type II and III. Type IV: consists of miscellaneous group of unclassifiable mutations. [:] [:] Function ANT3_HUMAN Most important serine protease inhibitor in plasma that regulates the blood coagulation cascade. AT-III inhibits thrombin, matriptase-3/TMPRSS7, as well as factors IXa, Xa and XIa. Its inhibitory activity is greatly enhanced in the presence of heparin. 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 PubMed Many of the late-onset dementias, including Alzheimer's disease and the prion encephalopathies, arise from the aberrant aggregation of individual proteins. The serpin family of serine protease inhibitors provides a well-defined structural example of such pathological aggregation, as its mutant variants readily form long-chain polymers, resulting in diseases ranging from thrombosis to dementia. The intermolecular linkages result from the insertion of the reactive site loop of one serpin molecule into the middle strand (s4A) position of the A beta-sheet of another molecule. We define here the structural requirements for small peptides to competitively bind to and block the s4A position to prevent this intermolecular linkage and polymerisation. The entry and anchoring of blocking-peptides is facilitated by the presence of a threonine which inserts into the site equivalent to P8 of s4A. But the critical requirement for small blocking-peptides is demonstrated in crystallographic structures of the complexes formed with selected tri- and tetrapeptides. These structures indicate that the binding is primarily due to the insertion of peptide hydrophobic side-chains into the P4 and P6 sites of s4A. The findings allow the rational design of synthetic blocking-peptides small enough to be suitable for mimetic design. This is demonstrated here with a tetrapeptide that preferentially blocks the polymerisation of a pathologically unstable serpin commonly present in people of European descent. How small peptides block and reverse serpin polymerisation.,Zhou A, Stein PE, Huntington JA, Sivasothy P, Lomas DA, Carrell RW J Mol Biol. 2004 Sep 17;342(3):931-41. PMID:15342247 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Antithrombin 3D structures

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