1AWF

NOVEL COVALENT THROMBIN INHIBITOR FROM PLANT EXTRACT


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.20 Å
  • R-Value Work: 0.196 
  • R-Value Observed: 0.196 

wwPDB Validation 3D Report Full Report


This is version 1.4 of the entry. See complete history


Literature

Novel natural product 5,5-trans-lactone inhibitors of human alpha-thrombin: mechanism of action and structural studies.

Weir, M.P.Bethell, S.S.Cleasby, A.Campbell, C.J.Dennis, R.J.Dix, C.J.Finch, H.Jhoti, H.Mooney, C.J.Patel, S.Tang, C.M.Ward, M.Wonacott, A.J.Wharton, C.W.

(1998) Biochemistry 37: 6645-6657

  • DOI: 10.1021/bi972499o
  • Primary Citation of Related Structures:  
    1AWF, 1AWH

  • PubMed Abstract: 
  • 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 ...

    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.


    Organizational Affiliation

    Glaxo Wellcome Medicines Research Centre, Stevenage, Hertfordshire, U.K.



Macromolecules
Find similar proteins by:  (by identity cutoff)  |  Structure
Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
ALPHA THROMBINL36Homo sapiensMutation(s): 0 
Gene Names: F2
EC: 3.4.21.5
Find proteins for P00734 (Homo sapiens)
Explore P00734 
Go to UniProtKB:  P00734
NIH Common Fund Data Resources
PHAROS  P00734
Protein Feature View
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  • Reference Sequence
Find similar proteins by:  (by identity cutoff)  |  Structure
Entity ID: 2
MoleculeChainsSequence LengthOrganismDetailsImage
ALPHA THROMBINH259Homo sapiensMutation(s): 0 
Gene Names: F2
EC: 3.4.21.5
Find proteins for P00734 (Homo sapiens)
Explore P00734 
Go to UniProtKB:  P00734
NIH Common Fund Data Resources
PHAROS  P00734
Protein Feature View
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  • Reference Sequence
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Entity ID: 3
MoleculeChainsSequence LengthOrganismDetailsImage
HIRUGENI10Hirudo medicinalisMutation(s): 0 
Find proteins for P01050 (Hirudo medicinalis)
Explore P01050 
Go to UniProtKB:  P01050
Protein Feature View
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  • Reference Sequence
Small Molecules
Ligands 1 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
GR4
Query on GR4

Download CCD File 
H
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
C38 H56 O14
ICEIDITWEARXBX-KIWBXHNRSA-N
 Ligand Interaction
Modified Residues  1 Unique
IDChainsTypeFormula2D DiagramParent
TYS
Query on TYS
IL-PEPTIDE LINKINGC9 H11 N O6 STYR
External Ligand Annotations 
IDBinding Affinity (Sequence Identity %)
GR4Ki :  970   nM  PDBBind
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.20 Å
  • R-Value Work: 0.196 
  • R-Value Observed: 0.196 
  • Space Group: C 1 2 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 71.92α = 90
b = 71.84β = 100.39
c = 73.01γ = 90
Software Package:
Software NamePurpose
MADNESdata collection
CCP4data reduction
X-PLORmodel building
X-PLORrefinement
MADNESdata reduction
CCP4data scaling
X-PLORphasing

Structure Validation

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Entry History 

Deposition Data

Revision History 

  • Version 1.0: 1998-10-28
    Type: Initial release
  • Version 1.1: 2008-03-24
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Atomic model, Database references, Derived calculations, Non-polymer description, Structure summary, Version format compliance
  • Version 1.3: 2018-04-04
    Changes: Data collection, Other
  • Version 1.4: 2018-04-18
    Changes: Data collection