1etr

REFINED 2.3 ANGSTROMS X-RAY CRYSTAL STRUCTURE OF BOVINE THROMBIN COMPLEXES FORMED WITH THE BENZAMIDINE AND ARGININE-BASED THROMBIN INHIBITORS NAPAP, 4-TAPAP AND MQPA: A STARTING POINT FOR IMPROVING ANTITHROMBOTICS

spinqualitylabelsall models 1etr, resolution 2.20Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 1etr is a 2 chain structure with sequence from Bovin. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: MIT Related: 1ets, 1ett Activity: Thrombin, with EC number 3.4.21.5 Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function [THRB_BOVIN] 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 (By similarity). 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 Well-diffracting crystals of bovine epsilon-thrombin in complex with several "non-peptidic" benzamidine and arginine-based thrombin inhibitors have been obtained by co-crystallization. The 2.3 A crystal structures of three complexes formed either with NAPAP, 4-TAPAP, or MQPA, were solved by Patterson search methods and refined to crystallographic R-values of 0.167 to 0.178. The active-site environment of thrombin is only slightly affected by binding of the different inhibitors; in particular, the exposed "60-insertion loop" essentially maintains its typical projecting structure. The D-stereoisomer of NAPAP and the L-stereoisomer of MQPA bind to thrombin with very similar conformations, as previously inferred from their binding to bovine trypsin; the arginine side-chain of the latter inserts into the specificity pocket in a "non-canonical" manner. The L-stereoisomer of 4-TAPAP, whose binding geometry towards trypsin was only poorly defined, is bound to the thrombin active-site in a compact conformation. In contrast to NAPAP, the distal p-amidino/guanidino groups of 4-TAPAP and MQPA do not interact with the carboxylate group of Asp189 in the thrombin specificity pocket in a "symmetrical" twin N-twin O manner, but through "lateral" single N-twin O contacts; in contrast to the p-amidino group of 4-TAPAP, however, the guanidyl group of MQPA packs favourably in the pocket due to an elaborate hydrogen bond network, which includes two entrapped water molecules. These thrombin structures confirm previous conclusions of the important role of the intermolecular hydrogen bonds formed with Gly216, and of the good sterical fit of the terminal bulky hydrophobic inhibitor groups with the hydrophobic aryl binding site and the S2-cavity, respectively, for tight thrombin active site binding of these non-peptidic inhibitors. These accurate crystal structures are presumed to be excellent starting points for the design and the elaboration of improved antithrombotics. Refined 2.3 A X-ray crystal structure of bovine thrombin complexes formed with the benzamidine and arginine-based thrombin inhibitors NAPAP, 4-TAPAP and MQPA. A starting point for improving antithrombotics.,Brandstetter H, Turk D, Hoeffken HW, Grosse D, Sturzebecher J, Martin PD, Edwards BF, Bode W J Mol Biol. 1992 Aug 20;226(4):1085-99. PMID:1518046 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Thrombin 3D Structures

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