1awf: Difference between revisions
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[[Image:1awf.gif|left|200px]] | [[Image:1awf.gif|left|200px]] | ||
'''NOVEL COVALENT THROMBIN INHIBITOR FROM PLANT EXTRACT''' | {{Structure | ||
|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> | |||
|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> | |||
|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] | |||
|GENE= | |||
}} | |||
'''NOVEL COVALENT THROMBIN INHIBITOR FROM PLANT EXTRACT''' | |||
==Overview== | ==Overview== | ||
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==About this Structure== | ==About this Structure== | ||
1AWF is a [ | 1AWF is a [[Protein complex]] structure of sequences from [http://en.wikipedia.org/wiki/Hirudo_medicinalis Hirudo medicinalis] and [http://en.wikipedia.org/wiki/Homo_sapiens Homo sapiens]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1AWF OCA]. | ||
==Reference== | ==Reference== | ||
Novel natural product 5,5-trans-lactone inhibitors of human alpha-thrombin: mechanism of action and structural studies., Weir MP, Bethell SS, Cleasby A, Campbell CJ, Dennis RJ, Dix CJ, Finch H, Jhoti H, Mooney CJ, Patel S, Tang CM, Ward M, Wonacott AJ, Wharton CW, Biochemistry. 1998 May 12;37(19):6645-57. PMID:[http:// | Novel natural product 5,5-trans-lactone inhibitors of human alpha-thrombin: mechanism of action and structural studies., Weir MP, Bethell SS, Cleasby A, Campbell CJ, Dennis RJ, Dix CJ, Finch H, Jhoti H, Mooney CJ, Patel S, Tang CM, Ward M, Wonacott AJ, Wharton CW, Biochemistry. 1998 May 12;37(19):6645-57. PMID:[http://www.ncbi.nlm.nih.gov/pubmed/9578548 9578548] | ||
[[Category: Hirudo medicinalis]] | [[Category: Hirudo medicinalis]] | ||
[[Category: Homo sapiens]] | [[Category: Homo sapiens]] | ||
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[[Category: trypsin like proteinase]] | [[Category: trypsin like proteinase]] | ||
''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Mar 20 10:03:06 2008'' | ||
Revision as of 11:03, 20 March 2008
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| , resolution 2.2Å | |||||||
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| Sites: | |||||||
| Ligands: | |||||||
| Activity: | Thrombin, with EC number 3.4.21.5 | ||||||
| Coordinates: | save as pdb, mmCIF, xml | ||||||
NOVEL COVALENT THROMBIN INHIBITOR FROM PLANT EXTRACT
OverviewOverview
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.
DiseaseDisease
Known diseases associated with this structure: Dysprothrombinemia OMIM:[176930], Hyperprothrombinemia OMIM:[176930], Hypoprothrombinemia OMIM:[176930]
About this StructureAbout this Structure
1AWF is a Protein complex structure of sequences from Hirudo medicinalis and Homo sapiens. Full crystallographic information is available from OCA.
ReferenceReference
Novel natural product 5,5-trans-lactone inhibitors of human alpha-thrombin: mechanism of action and structural studies., Weir MP, Bethell SS, Cleasby A, Campbell CJ, Dennis RJ, Dix CJ, Finch H, Jhoti H, Mooney CJ, Patel S, Tang CM, Ward M, Wonacott AJ, Wharton CW, Biochemistry. 1998 May 12;37(19):6645-57. PMID:9578548
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