1SFI

High resolution structure of a potent, cyclic protease inhibitor from sunflower seeds


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.65 Å
  • R-Value Free: 0.204 
  • R-Value Work: 0.175 

wwPDB Validation 3D Report Full Report


This is version 1.3 of the entry. See complete history


Literature

High-resolution structure of a potent, cyclic proteinase inhibitor from sunflower seeds.

Luckett, S.Garcia, R.S.Barker, J.J.Konarev, A.V.Shewry, P.R.Clarke, A.R.Brady, R.L.

(1999) J Mol Biol 290: 525-533

  • DOI: 10.1006/jmbi.1999.2891
  • Primary Citation of Related Structures:  
    1SFI

  • PubMed Abstract: 
  • Proteinaceous serine proteinase inhibitors are widespread throughout the plant kingdom where they play an important role in protection against pests and pathogens. Here, we describe the isolation and characterisation of a novel 14 amino acid residue ...

    Proteinaceous serine proteinase inhibitors are widespread throughout the plant kingdom where they play an important role in protection against pests and pathogens. Here, we describe the isolation and characterisation of a novel 14 amino acid residue cyclic peptide from sunflower seeds, which is a potent inhibitor of trypsin (Ki=100 pM). The crystal structure of this peptide in complex with bovine beta-trypsin shows both sequence and conformational similarity with the trypsin-reactive loop of the Bowman-Birk family of serine proteinase inhibitors. This inhibitor, however, is unique in being monofunctional, cyclic and far shorter (14 amino acid residues) than inhibitors belonging to this family (typically 60-70 amino acid residues). The high potency of this peptide is likely to arise from the considerable structural rigidity achieved through its cyclic nature which is further stabilised by a single internal disulphide bond. This study helps delineate the minimal unit required for effective peptide inhibitors of serine proteinases, and will assist in the further design of inhibitors to this widespread class of enzymes.


    Organizational Affiliation

    Department of Biochemistry, University of Bristol, Bristol, BS8 1TD, UK.



Macromolecules
Find similar proteins by:  (by identity cutoff)  |  Structure
Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
TRYPSINA223Bos taurusMutation(s): 0 
EC: 3.4.21.4
Find proteins for P00760 (Bos taurus)
Explore P00760 
Go to UniProtKB:  P00760
Protein Feature View
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  • Reference Sequence
  • Find similar proteins by:  Sequence   |   Structure
Entity ID: 2
MoleculeChainsSequence LengthOrganismDetailsImage
Trypsin inhibitor 1I14Helianthus annuusMutation(s): 0 
Gene Names: sfti1
Find proteins for Q4GWU5 (Helianthus annuus)
Explore Q4GWU5 
Go to UniProtKB:  Q4GWU5
Protein Feature View
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  • Reference Sequence
Small Molecules
Ligands 2 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
SO4
Query on SO4

Download CCD File 
A
SULFATE ION
O4 S
QAOWNCQODCNURD-UHFFFAOYSA-L
 Ligand Interaction
CA
Query on CA

Download CCD File 
A
CALCIUM ION
Ca
BHPQYMZQTOCNFJ-UHFFFAOYSA-N
 Ligand Interaction
Biologically Interesting Molecules (External Reference) 1 Unique
Entity ID: 2
IDChainsNameType/Class2D Diagram3D Interactions
PRD_001097
Query on PRD_001097
ITrypsin inhibitor 1Polypeptide /  Trypsin inhibitor

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Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.65 Å
  • R-Value Free: 0.204 
  • R-Value Work: 0.175 
  • Space Group: P 21 21 21
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 60.61α = 90
b = 64.43β = 90
c = 70.62γ = 90
Software Package:
Software NamePurpose
DENZOdata reduction
SCALEPACKdata scaling
AMoREphasing
REFMACrefinement

Structure Validation

View Full Validation Report



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 1999-07-09
    Type: Initial release
  • Version 1.1: 2008-03-03
    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: 2016-11-09
    Changes: Structure summary