1UTM

Trypsin specificity as elucidated by LIE calculations, X-ray structures and association constant measurements


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.50 Å
  • R-Value Free: 0.217 
  • R-Value Work: 0.189 
  • R-Value Observed: 0.189 

wwPDB Validation 3D Report Full Report


This is version 1.3 of the entry. See complete history


Literature

Trypsin Specificity as Elucidated by Lie Calculations, X-Ray Structures, and Association Constant Measurements

Leiros, H.-K.S.Brandsdal, B.O.Andersen, O.A.Os, V.Leiros, I.Helland, R.Otlewski, J.Willassen, N.P.Smalas, A.O.

(2004) Protein Sci 13: 1056

  • DOI: 10.1110/ps.03498604
  • Structures With Same Primary Citation

  • PubMed Abstract: 
  • The variation in inhibitor specificity for five different amine inhibitors bound to CST, BT, and the cold-adapted AST has been studied by use of association constant measurements, structural analysis of high-resolution crystal structures, and the LIE ...

    The variation in inhibitor specificity for five different amine inhibitors bound to CST, BT, and the cold-adapted AST has been studied by use of association constant measurements, structural analysis of high-resolution crystal structures, and the LIE method. Experimental data show that AST binds the 1BZA and 2BEA inhibitors 0.8 and 0.5 kcal/mole more strongly than BT. However, structural interactions and orientations of the inhibitors within the S1 site have been found to be virtually identical in the three enzymes studied. For example, the four water molecules in the inhibitor-free structures of AST and BT are channeled into similar positions in the S1 site, and the nitrogen atom(s) of the inhibitors are found in two cationic binding sites denoted Position1 and Position2. The hydrophobic binding contributions for all five inhibitors, estimated by the LIE calculations, are also in the same order (-2.1 +/- 0.2 kcal/mole) for all three enzymes. Our hypothesis is therefore that the observed variation in inhibitor binding arises from different electrostatic interactions originating from residues outside the S1 site. This is well illustrated by AST, in which Asp 150 and Glu 221B, despite some distance from the S1 binding site, lower the electrostatic potential of the S1 site and thus enhance substrate binding. Because the trends in the experimentally determined binding energies were reproduced by the LIE calculations after adding the contribution from long-range interactions, we find this method very suitable for rational studies of protein-substrate interactions.


    Organizational Affiliation

    University of Tromsø, N-9037 Tromsø, Norway.



Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
TRYPSIN IA242Salmo salarMutation(s): 0 
EC: 3.4.21.4
Find proteins for P35031 (Salmo salar)
Explore P35031 
Go to UniProtKB:  P35031
Protein Feature View
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  • Reference Sequence
Small Molecules
Ligands 2 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
PEA
Query on PEA

Download CCD File 
A
2-PHENYLETHYLAMINE
C8 H12 N
BHHGXPLMPWCGHP-UHFFFAOYSA-O
 Ligand Interaction
CA
Query on CA

Download CCD File 
A
CALCIUM ION
Ca
BHPQYMZQTOCNFJ-UHFFFAOYSA-N
 Ligand Interaction
External Ligand Annotations 
IDBinding Affinity (Sequence Identity %)
PEAKd:  971000   nM  Binding MOAD
PEAKd :  972000   nM  PDBBind
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.50 Å
  • R-Value Free: 0.217 
  • R-Value Work: 0.189 
  • R-Value Observed: 0.189 
  • Space Group: P 21 21 2
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 74.941α = 90
b = 85.085β = 90
c = 32.185γ = 90
Software Package:
Software NamePurpose
X-PLORrefinement
DENZOdata reduction
SCALAdata scaling

Structure Validation

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Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2004-01-09
    Type: Initial release
  • Version 1.1: 2011-06-02
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Version format compliance
  • Version 1.3: 2019-07-24
    Changes: Advisory, Data collection