1awf: Difference between revisions
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|PDB= 1awf |SIZE=350|CAPTION= <scene name='initialview01'>1awf</scene>, resolution 2.2Å | |PDB= 1awf |SIZE=350|CAPTION= <scene name='initialview01'>1awf</scene>, resolution 2.2Å | ||
|SITE= <scene name='pdbsite=NUL:Catalytic+Triad+Of+SER+Proteinases'>NUL</scene> | |SITE= <scene name='pdbsite=NUL:Catalytic+Triad+Of+SER+Proteinases'>NUL</scene> | ||
|LIGAND= <scene name='pdbligand=GR4:R3-ACETOXY-17-(1-FORMYL-5-METHYL-3-OXO-HEX-4-ENYL)-12,16-DIHYDROXY-14-HYDROXYMETHYL-4,10,13-TRIMETHYL-2,3,4,5,6,9,10,11,12,13,14,15,16,17-TETRADECAHYDRO-1H-CYCLOPENTA[A]PHENANTHRENE-4-CARBOXYLIC ACID IDOPYRANOSYL ESTER'>GR4</scene> | |LIGAND= <scene name='pdbligand=GR4:R3-ACETOXY-17-(1-FORMYL-5-METHYL-3-OXO-HEX-4-ENYL)-12,16-DIHYDROXY-14-HYDROXYMETHYL-4,10,13-TRIMETHYL-2,3,4,5,6,9,10,11,12,13,14,15,16,17-TETRADECAHYDRO-1H-CYCLOPENTA[A]PHENANTHRENE-4-CARBOXYLIC+ACID+IDOPYRANOSYL+ESTER'>GR4</scene>, <scene name='pdbligand=TYS:SULFONATED+TYROSINE'>TYS</scene> | ||
|ACTIVITY= [http://en.wikipedia.org/wiki/Thrombin Thrombin], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.4.21.5 3.4.21.5] | |ACTIVITY= <span class='plainlinks'>[http://en.wikipedia.org/wiki/Thrombin Thrombin], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.4.21.5 3.4.21.5] </span> | ||
|GENE= | |GENE= | ||
|DOMAIN= | |||
|RELATEDENTRY= | |||
|RESOURCES=<span class='plainlinks'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=1awf FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1awf OCA], [http://www.ebi.ac.uk/pdbsum/1awf PDBsum], [http://www.rcsb.org/pdb/explore.do?structureId=1awf RCSB]</span> | |||
}} | }} | ||
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==Overview== | ==Overview== | ||
High-throughput screening of methanolic extracts from the leaves of the plant Lantana camara identified potent inhibitors of human alpha-thrombin, which were shown to be 5,5-trans-fused cyclic lactone euphane triterpenes [O'Neill et al. (1998) J. Nat. Prod. (submitted for publication)]. Proflavin displacement studies showed the inhibitors to bind at the active site of alpha-thrombin and alpha-chymotrypsin. Kinetic analysis of alpha-thrombin showed tight-binding reversible competitive inhibition by both compounds, named GR133487 and GR133686, with respective kon values at pH 8.4 of 1.7 x 10(6) s-1 M-1 and 4.6 x 10(6) s-1 M-1. Electrospray ionization mass spectrometry of thrombin/inhibitor complexes showed the tight-bound species to be covalently attached, suggesting acyl-enzyme formation by reaction of the active-site Ser195 with the trans-lactone carbonyl. X-ray crystal structures of alpha-thrombin/GR133686 (3.0 A resolution) and alpha-thrombin/GR133487 (2.2 A resolution) complexes showed continuous electron density between Ser195 and the ring-opened lactone carbonyl, demonstrating acyl-enzyme formation. Turnover of inhibitor by alpha-thrombin was negligible and mass spectrometry of isolated complexes showed that reversal of inhibition occurs by reformation of the trans-lactone from the acyl-enzyme.The catalytic triad appears undisrupted and the inhibitor carbonyl occupies the oxyanion hole, suggesting the observed lack of turnover is due to exclusion of water for deacylation. The acyl-enzyme inhibitor hydroxyl is properly positioned for nucleophilic attack on the ester carbonyl and therefore relactonization; furthermore, the higher resolution structure of alpha-thrombin/GR133487 shows this hydroxyl to be effectively superimposable with the recently proposed deacylating water for peptide substrate hydrolysis [Wilmouth, R. C., et al. (1997) Nat. Struct.Biol. 4, 456-462], suggesting the alpha-thrombin/GR133487 complex may be a good model for this reaction. | High-throughput screening of methanolic extracts from the leaves of the plant Lantana camara identified potent inhibitors of human alpha-thrombin, which were shown to be 5,5-trans-fused cyclic lactone euphane triterpenes [O'Neill et al. (1998) J. Nat. Prod. (submitted for publication)]. Proflavin displacement studies showed the inhibitors to bind at the active site of alpha-thrombin and alpha-chymotrypsin. Kinetic analysis of alpha-thrombin showed tight-binding reversible competitive inhibition by both compounds, named GR133487 and GR133686, with respective kon values at pH 8.4 of 1.7 x 10(6) s-1 M-1 and 4.6 x 10(6) s-1 M-1. Electrospray ionization mass spectrometry of thrombin/inhibitor complexes showed the tight-bound species to be covalently attached, suggesting acyl-enzyme formation by reaction of the active-site Ser195 with the trans-lactone carbonyl. X-ray crystal structures of alpha-thrombin/GR133686 (3.0 A resolution) and alpha-thrombin/GR133487 (2.2 A resolution) complexes showed continuous electron density between Ser195 and the ring-opened lactone carbonyl, demonstrating acyl-enzyme formation. Turnover of inhibitor by alpha-thrombin was negligible and mass spectrometry of isolated complexes showed that reversal of inhibition occurs by reformation of the trans-lactone from the acyl-enzyme.The catalytic triad appears undisrupted and the inhibitor carbonyl occupies the oxyanion hole, suggesting the observed lack of turnover is due to exclusion of water for deacylation. The acyl-enzyme inhibitor hydroxyl is properly positioned for nucleophilic attack on the ester carbonyl and therefore relactonization; furthermore, the higher resolution structure of alpha-thrombin/GR133487 shows this hydroxyl to be effectively superimposable with the recently proposed deacylating water for peptide substrate hydrolysis [Wilmouth, R. C., et al. (1997) Nat. Struct.Biol. 4, 456-462], suggesting the alpha-thrombin/GR133487 complex may be a good model for this reaction. | ||
==About this Structure== | ==About this Structure== | ||
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[[Category: Jhoti, H.]] | [[Category: Jhoti, H.]] | ||
[[Category: Wonacott, A.]] | [[Category: Wonacott, A.]] | ||
[[Category: blood coagulation]] | [[Category: blood coagulation]] | ||
[[Category: complex (protease/inhibitor)]] | [[Category: complex (protease/inhibitor)]] | ||
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[[Category: trypsin like proteinase]] | [[Category: trypsin like proteinase]] | ||
''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sun Mar 30 18:48:55 2008'' | ||
