Experimental Data Snapshot

  • Method: SOLUTION NMR
  • Conformers Calculated: 100 
  • Conformers Submitted: 15 
  • Selection Criteria: structures with the least restraint violations 

wwPDB Validation   3D Report Full Report

This is version 1.3 of the entry. See complete history


PA1b, an insecticidal protein extracted from pea seeds (Pisum sativum): 1H-2-D NMR study and molecular modeling

Jouvensal, L.Quillien, L.Ferrasson, E.Rahbe, Y.Gueguen, J.Vovelle, F.

(2003) Biochemistry 42: 11915-11923

  • DOI: https://doi.org/10.1021/bi034803l
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 

    PA1b (pea albumin 1, subunit b) is a 37-amino acid cysteine-rich plant defense protein isolated from pea seeds (Pisum sativum). It induces short-term mortality in several pests, among which the cereal weevils Sitophilus sp. (Sitophilus oryzae, Sitophilus granarius, and Sitophilus zeamais) that are a major nuisance for stored cereals, all over the world. As such, PA1b is the first genuine protein phytotoxin specifically toxic to insects, which makes it a promising tool for seed weevil damage control. We have determined the 3-D solution structure of PA1b, using 2-D homonuclear proton NMR methods and molecular modeling. The primary sequence of the protein does not share similarities with other known toxins. It includes six cysteines forming three disulfide bridges. However, because of PA1b resistance to protease cleavage, conventional methods failed to establish the connectivity pattern. Our first attempts to assign the disulfide network from NOE data alone remained unsuccessful due to the tight packing of the cysteine residues within the core of the molecule. Yet, the use of ambiguous disulfide restraints within ARIA allowed us to establish that PA1b belongs to the inhibitor cystine-knot family. It exhibits the structural features that are characteristic of the knottin fold, namely, a triple-stranded antiparallel beta-sheet with a long flexible loop connecting the first to the second strand and a series of turns. A comparison of the structural properties of PA1b with that of structurally related proteins adopting a knottin fold and exhibiting a diverse range of biological activities shows that the electrostatic and lipophilic potentials at the surface of PA1b are very close to those found for the spider toxin ACTX-Hi:OB4219, thereby suggesting activity on ion channels.

  • Organizational Affiliation

    Centre de Biophysique Moléculaire, CNRS, Affiliated to Orleans University, Rue Charles Sadron, 45071 Orléans Cedex 2, France. jouvensa@cnrs-orleans.fr

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Pea Albumin 1, subunit b37Pisum sativumMutation(s): 0 
Membrane Entity: Yes 
Find proteins for P62931 (Pisum sativum)
Explore P62931 
Go to UniProtKB:  P62931
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP62931
Sequence Annotations
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Method: SOLUTION NMR
  • Conformers Calculated: 100 
  • Conformers Submitted: 15 
  • Selection Criteria: structures with the least restraint violations 

Structure Validation

View Full Validation Report

Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2003-11-25
    Type: Initial release
  • Version 1.1: 2008-04-29
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Version format compliance
  • Version 1.3: 2021-02-03
    Changes: Database references, Derived calculations