4CMS

X-RAY ANALYSES OF ASPARTIC PROTEINASES IV. STRUCTURE AND REFINEMENT AT 2.2 ANGSTROMS RESOLUTION OF BOVINE CHYMOSIN


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.20 Å
  • R-Value Observed: 0.158 

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This is version 1.3 of the entry. See complete history


Literature

X-ray analyses of aspartic proteinases. IV. Structure and refinement at 2.2 A resolution of bovine chymosin.

Newman, M.Safro, M.Frazao, C.Khan, G.Zdanov, A.Tickle, I.J.Blundell, T.L.Andreeva, N.

(1991) J Mol Biol 221: 1295-1309

  • Structures With Same Primary Citation

  • PubMed Abstract: 
  • The structure of calf chymosin (EC 3.4.23.3), the aspartic proteinase from the gastric mucosa, was solved using the technique of molecular replacement. We describe the use of different search models based on distantly related fungal aspartic proteina ...

    The structure of calf chymosin (EC 3.4.23.3), the aspartic proteinase from the gastric mucosa, was solved using the technique of molecular replacement. We describe the use of different search models based on distantly related fungal aspartic proteinases and investigate the effect of using only structurally conserved regions. The structure has been refined to a crystallographic R-factor of 17% at 2.2 A resolution with an estimated co-ordinate error of 0.21 A. In all, 136 water molecules have been located of which eight are internal. The structure of chymosin resembles that of pepsin and other aspartic proteinases. However, there is a considerable rearrangement of the active-site "flap" and, in particular, Tyr75 (pepsin numbering), which forms part of the specificity pockets S1 and S1'. This is probably a consequence of crystal packing. Electrostatic interactions on the edge of the substrate binding cleft appear to account for the restricted proteolysis of the natural substrate kappa-casein by chymosin. The local environment of invariant residues is examined, showing that structural constraints and side-chain hydrogen bonding can play an important role in the conservation of particular amino acids.


    Related Citations: 
    • Engineering Enzyme Sub-Site Specificity: Preparation, Kinetic Characterization and X-Ray Analysis at 2.0-Angstroms Resolution of Val111Phe Site-Mutated Calf Chymosin
      Strop, P., Sedlacek, J., Stys, J., Kaderabkova, Z., Blaha, I., Pavlickova, L., Pohl, J., Fabry, M., Kostka, V., Newman, M., Frazao, C., Shearer, A., Tickle, I.J., Blundell, T.L.
      (1990) Biochemistry 29: 9863

    Organizational Affiliation

    Department of Crystallography, Birbeck College, University of London, U.K.



Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
CHYMOSIN B
A
323Bos taurusMutation(s): 0 
Gene Names: CYMCPC
EC: 3.4.23.4
Find proteins for P00794 (Bos taurus)
Go to UniProtKB:  P00794
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.20 Å
  • R-Value Observed: 0.158 
  • Space Group: I 2 2 2
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 79.98α = 90
b = 114.12β = 90
c = 72.76γ = 90
Software Package:
Software NamePurpose
RESTRAINrefinement

Structure Validation

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Entry History 

Deposition Data

Revision History 

  • Version 1.0: 1991-11-07
    Type: Initial release
  • Version 1.1: 2008-03-03
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Version format compliance
  • Version 1.3: 2017-11-29
    Changes: Derived calculations, Other