Experimental Data Snapshot

  • Resolution: 1.80 Å
  • R-Value Free: 0.188 
  • R-Value Work: 0.172 
  • R-Value Observed: 0.172 

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X-ray crystallographic analyses of complexes between bovine beta-trypsin and Schiff base copper(II) or iron(III) chelates.

Toyota, E.Ng, K.K.Sekizaki, H.Itoh, K.Tanizawa, K.James, M.N.

(2001) J Mol Biol 305: 471-479

  • DOI: https://doi.org/10.1006/jmbi.2000.4303
  • Primary Citation of Related Structures:  
    1G3B, 1G3C, 1G3D, 1G3E

  • PubMed Abstract: 

    To establish the structural basis underlying the activity of a novel series of metal-chelate trypsin inhibitors, the structures of p-amidinosalicylidene-l-alaninato(aqua)copper(II) (1a), m-amidinosalicylidene-l-alaninato(aqua)copper(II) (1b), bis(p-amidinosalicylidene-l-alaninato)iron(III) (2a), and bis(m-amidinosalicylidene-l-alaninato)iron(III) (2b) bound to bovine beta-trypsin were studied by X-ray crystallography. The amidinium group of the inhibitor donates hydrogen bonds to Asp189, Gly219 and Ser190, as seen before in trypsin-benzamidine complexes. The copper(II) ion of 1a is situated away from trypsin's catalytic triad residues, and is octahedrally coordinated by a Schiff base and three water molecules. In contrast, the copper(II) ion of 1b is situated close to the catalytic triad and adopts a square pyramidal coordination geometry. The iron(III) ion of 2a is octahedrally coordinated by two Schiff base ligands and, like the copper(II) ion of 1a, is situated away from the catalytic triad. The p-amidinophenyl ring of a second Schiff base ligand of 2a is directed toward a hydrophobic groove formed by Trp215 and Leu99. Finally, the iron(III) ion of 2b appears to be replaced by magnesium(II), which is octahedrally coordinated by a Schiff base, Gln192 and two water molecules. One of the Schiff base ligands seen in the trypsin-2a complex or in the unbound form of 2b is replaced by water molecules and Gln192. His57 and Ser195 form water-mediated interactions with the magnesium(II) ion of 2b, and Ser195 also forms a hydrogen bond with the phenolic oxygen atom of the Schiff base ligand. These structures reveal a novel mode of interaction between metal-chelate inhibitors and serine proteases, thus providing a structural basis for the development of more potent inhibitors against a variety of trypsin-like enzymes.

  • Organizational Affiliation

    Faculty of Pharmaceutical Sciences, Health Sciences University of Hokkaido, Ishikari-Tobestu, Hokkaido 061-0293, Japan.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
BETA-TRYPSIN228Bos taurusMutation(s): 0 
Find proteins for P00760 (Bos taurus)
Explore P00760 
Go to UniProtKB:  P00760
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP00760
Sequence Annotations
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Resolution: 1.80 Å
  • R-Value Free: 0.188 
  • R-Value Work: 0.172 
  • R-Value Observed: 0.172 
  • Space Group: P 21 21 21
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 63.77α = 90
b = 63.29β = 90
c = 69.25γ = 90
Software Package:
Software NamePurpose
DENZOdata reduction
SCALEPACKdata scaling

Structure Validation

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Ligand Structure Quality Assessment 

Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2001-01-17
    Type: Initial release
  • Version 1.1: 2008-04-27
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Version format compliance
  • Version 1.3: 2018-04-04
    Changes: Data collection
  • Version 1.4: 2023-08-09
    Changes: Data collection, Database references, Derived calculations, Refinement description