2CI2

CRYSTAL AND MOLECULAR STRUCTURE OF THE SERINE PROTEINASE INHIBITOR CI-2 FROM BARLEY SEEDS


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2 Å

wwPDB Validation 3D Report Full Report


This is version 1.3 of the entry. See complete history

Literature

Crystal and molecular structure of the serine proteinase inhibitor CI-2 from barley seeds.

McPhalen, C.A.James, M.N.

(1987) Biochemistry 26: 261-269


  • PubMed Abstract: 
  • Chymotrypsin inhibitor 2 (CI-2), a serine proteinase inhibitor from barley seeds, has been crystallized and its three-dimensional structure determined at 2.0-A resolution by the molecular replacement method. The structure has been refined by restrain ...

    Chymotrypsin inhibitor 2 (CI-2), a serine proteinase inhibitor from barley seeds, has been crystallized and its three-dimensional structure determined at 2.0-A resolution by the molecular replacement method. The structure has been refined by restrained-parameter least-squares methods to a crystallographic R factor (= sigma parallel Fo magnitude of-Fo parallel/sigma magnitude of Fo) o of 0.198. CI-2 is a member of the potato inhibitor 1 family. It lacks the characteristic stabilizing disulfide bonds of most other members of serine proteinase inhibitor families. The body of CI-2 shows few conformational changes between the free inhibitor and the previously reported structure of CI-2 in complex with subtilisin Novo [McPhalen, C.A., Svendsen, I., Jonassen, I., & James, M.N.G. (1985) Proc. Natl. Acad. Sci. U.S.A. 82, 7242-7246]. However, the reactive site loop has some significant conformational differences between the free inhibitor and its complexed form. The residues in this segment of polypeptide exhibit relatively large thermal motion parameters and some disorder in the uncomplexed form of the inhibitor. The reactive site bond is between Met-59I and Glu-60I in the consecutive sequential numbering of CI-2 (Met-60-Glu-61 according to the alignment of Svendsen et al. [Svendsen, I., Hejgaard, J., & Chavan, J.K. (1984) Carlsberg Res. Commun. 49, 493-502]). The network of hydrogen bonds and electrostatic interactions stabilizing the conformation of the reactive site loop is much less extensive in the free than in the complexed inhibitor.


    Related Citations: 
    • Preliminary Crystallographic Data for the Serine Protease Inhibitor Ci-2 from Barley Seeds
      Mcphalen, C.A.,Evans, C.,Hayakawa, K.,Jonassen, I.,Svendsen, I.,James, M.N.G.
      (1983) J.Mol.Biol. 168: 445
    • Comparison of the Solution and X-Ray Structures of Barley Serine Proteinase Inhibitor 2
      Clore, G.M.,Gronenborn, A.M.,James, M.N.G.,Kjaer, M.,Mcphalen, C.A.,Poulsen, F.M.
      (1987) Protein Eng. 1: 313
    • Crystal and Molecular Structure of Chymotrypsin Inhibitor 2 from Barley Seeds in Complex with Subtilisin Novo
      Mcphalen, C.A.,Svendsen, I.,Jonassen, I.,James, M.N.G.
      (1985) Proc.Natl.Acad.Sci.USA 82: 7242



Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
CHYMOTRYPSIN INHIBITOR 2
I
83Hordeum vulgareMutation(s): 0 
Find proteins for P01053 (Hordeum vulgare)
Go to UniProtKB:  P01053
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2 Å
  • Space Group: P 6 2 2
Unit Cell:
Length (Å)Angle (°)
a = 69.015α = 90.00
b = 69.015β = 90.00
c = 52.890γ = 120.00
Software Package:
Software NamePurpose
PROLSQrefinement

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 1988-09-07
    Type: Initial release
  • Version 1.1: 2008-03-10
    Type: Version format compliance
  • Version 1.2: 2011-07-13
    Type: Version format compliance
  • Version 1.3: 2017-11-29
    Type: Derived calculations, Other