Experimental Data Snapshot

  • Resolution: 1.90 Å

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Deleterious effects of beta-branched residues in the S1 specificity pocket of Streptomyces griseus proteinase B (SGPB): crystal structures of the turkey ovomucoid third domain variants Ile18I, Val18I, Thr18I, and Ser18I in complex with SGPB.

Bateman, K.S.Anderson, S.Lu, W.Qasim, M.A.Laskowski Jr., M.James, M.N.

(2000) Protein Sci 9: 83-94

  • DOI: https://doi.org/10.1110/ps.9.1.83
  • Primary Citation of Related Structures:  
    1CSO, 1CT0, 1CT2, 1CT4

  • PubMed Abstract: 

    Turkey ovomucoid third domain (OMTKY3) is a canonical inhibitor of serine proteinases. Upon complex formation, the inhibitors fully exposed P1 residue becomes fully buried in the preformed cavity of the enzyme. All 20 P1 variants of OMTKY3 have been obtained by recombinant DNA technology and their equilibrium association constants have been measured with six serine proteinases. To rationalize the trends observed in this data set, high resolution crystal structures have been determined for OMTKY3 P1 variants in complex with the bacterial serine proteinase, Streptomyces griseus proteinase B (SGPB). Four high resolution complex structures are being reported in this paper; the three beta-branched variants, Ile18I, Val18I, and Thr18I, determined to 2.1, 1.6, and 1.7 A resolution, respectively, and the structure of the Ser18I variant complex, determined to 1.9 A resolution. Models of the Cys18I, Hse18I, and Ape18I variant complexes are also discussed. The beta-branched side chains are not complementary to the shape of the S1 binding pocket in SGPB, in contrast to that of the wild-type gamma-branched P1 residue for OMTKY3, Leu18I. Chi1 angles of approximately 40 degrees are imposed on the side chains of Ile18I, Val18I, and Thr18I within the S1 pocket. Dihedral angles of +60 degrees, -60 degrees, or 180 degrees are more commonly observed but 40 degrees is not unfavorable for the beta-branched side chains. Thr18I Ogamma1 also forms a hydrogen bond with Ser195 Ogamma in this orientation. The Ser18I side chain adopts two alternate conformations within the S1 pocket of SGPB, suggesting that the side chain is not stable in either conformation.

  • Organizational Affiliation

    Medical Research Council of Canada Group in Protein Structure and Function, Department of Biochemistry, University of Alberta, Edmonton.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
PROTEINASE BA [auth E]185Streptomyces griseusMutation(s): 0 
Find proteins for P00777 (Streptomyces griseus)
Explore P00777 
Go to UniProtKB:  P00777
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP00777
Sequence Annotations
  • Reference Sequence
Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 2
MoleculeChains Sequence LengthOrganismDetailsImage
OVOMUCOID INHIBITORB [auth I]51Meleagris gallopavoMutation(s): 1 
Find proteins for P68390 (Meleagris gallopavo)
Explore P68390 
Go to UniProtKB:  P68390
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP68390
Sequence Annotations
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Resolution: 1.90 Å
  • Space Group: P 1 21 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 45.492α = 90
b = 54.736β = 119.21
c = 45.592γ = 90
Software Package:
Software NamePurpose
DIPdata collection
SCALEPACKdata scaling
X-PLORmodel building
DIPdata reduction

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2000-01-12
    Type: Initial release
  • Version 1.1: 2008-04-27
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Version format compliance