Experimental Data Snapshot

  • Resolution: 1.63 Å
  • R-Value Free: 0.255 
  • R-Value Work: 0.193 
  • R-Value Observed: 0.193 

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This is version 1.4 of the entry. See complete history


Crystal structure at 1.63 A resolution of the native form of porcine beta-trypsin: revealing an acetate ion binding site and functional water network.

Johnson, A.Gautham, N.Pattabhi, V.

(1999) Biochim Biophys Acta 1435: 7-21

  • DOI: https://doi.org/10.1016/s0167-4838(99)00202-2
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 

    The active center of a serine protease is the catalytic triad composed of His-57, Ser-195 and Asp-102. The existing crystal structure data on serine proteases have not fully answered a number of fundamental questions relating to the catalytic activity of serine proteases. The new high resolution native porcine beta-trypsin (BPT) structure is aimed at extending the knowledge on the conformation of the active site and the ordered water structure within and around the active site. The crystal structure of BPT has been determined at 1.63 A resolution. An acetate ion bound at the active site of a trypsin molecule by both classical hydrogen bonds and C-HellipsisO hydrogen bonds has been identified for the first time. A large network of water molecules extending from the recognition amino acid Asp-184 to the entry of the active site has been observed in the BPT structure. A detailed comparison with inhibitor complexes and autolysates indicates that the sulfate ion and the acetate ion bind at the same site of the trypsin molecule. The Ser-195 Cbeta-Ogamma-His-57 Nepsilon angle in the catalytic triad of BPT is intermediate between the corresponding values of the complex and native structure due to acetate ion binding. The network of waters from the recognition amino acid to the active site entry is probably the first ever complete picture of functional waters around the active site. Structural comparisons show that the functional waters involved in the binding of small molecule inhibitors and protease inhibitors are distinctly different.

  • Organizational Affiliation

    Department of Crystallography and Biophysics, University of Madras, Guindy Campus, Guindy, Chennai, India.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
BETA TRYPSIN223Sus scrofaMutation(s): 0 
Find proteins for P00761 (Sus scrofa)
Explore P00761 
Go to UniProtKB:  P00761
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP00761
Sequence Annotations
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Resolution: 1.63 Å
  • R-Value Free: 0.255 
  • R-Value Work: 0.193 
  • R-Value Observed: 0.193 
  • Space Group: P 21 21 21
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 78α = 90
b = 53.9β = 90
c = 47.26γ = 90
Software Package:
Software NamePurpose
XDSdata scaling
AUTOMARdata reduction
X-PLORmodel building
XDSdata reduction

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2000-06-14
    Type: Initial release
  • Version 1.1: 2008-04-26
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Version format compliance
  • Version 1.3: 2017-10-04
    Changes: Refinement description
  • Version 1.4: 2023-08-16
    Changes: Data collection, Database references, Derived calculations, Refinement description