1CEH

STRUCTURE AND FUNCTION OF THE CATALYTIC SITE MUTANT ASP99ASN OF PHOSPHOLIPASE A2: ABSENCE OF CONSERVED STRUCTURAL WATER


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.90 Å
  • R-Value Work: 0.185 
  • R-Value Observed: 0.185 

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This is version 1.2 of the entry. See complete history


Literature

Structure and function of the catalytic site mutant Asp 99 Asn of phospholipase A2: absence of the conserved structural water.

Kumar, A.Sekharudu, C.Ramakrishnan, B.Dupureur, C.M.Zhu, H.Tsai, M.D.Sundaralingam, M.

(1994) Protein Sci 3: 2082-2088

  • DOI: 10.1002/pro.5560031121
  • Primary Citation of Related Structures:  
    1CEH

  • PubMed Abstract: 
  • To probe the role of the Asp-99 ... His-48 pair in phospholipase A2 (PLA2) catalysis, the X-ray structure and kinetic characterization of the mutant Asp-99-->Asn-99 (D99N) of bovine pancreatic PLA2 was undertaken. Crystals of D99N belong to the trigonal space group P3(1)21 and were isomorphous to the wild type (WT) (Noel JP et al ...

    To probe the role of the Asp-99 ... His-48 pair in phospholipase A2 (PLA2) catalysis, the X-ray structure and kinetic characterization of the mutant Asp-99-->Asn-99 (D99N) of bovine pancreatic PLA2 was undertaken. Crystals of D99N belong to the trigonal space group P3(1)21 and were isomorphous to the wild type (WT) (Noel JP et al., 1991, Biochemistry 30:11801-11811). The 1.9-A X-ray structure of the mutant showed that the carbonyl group of Asn-99 side chain is hydrogen bonded to His-48 in the same way as that of Asp-99 in the WT, thus retaining the tautomeric form of His-48 and the function of the enzyme. The NH2 group of Asn-99 points away from His-48. In contrast, in the D102N mutant of the protease enzyme trypsin, the NH2 group of Asn-102 is hydrogen bonded to His-57 resulting in the inactive tautomeric form and hence the loss of enzymatic activity. Although the geometry of the catalytic triad in the PLA2 mutant remains the same as in the WT, we were surprised that the conserved structural water, linking the catalytic site with the ammonium group of Ala-1 of the interfacial site, was ejected by the proximity of the NH2 group of Asn-99. The NH2 group now forms a direct hydrogen bond with the carbonyl group of Ala-1.


    Related Citations: 
    • Phospholipase A2 Engineering. X-Ray Structural and Functional Evidence for the Interaction of Lysine-56 with Substrates
      Noel, J.P., Bingman, C.A., Deng, T., Dupureur, C.M., Hamilton, K.J., Jiang, R.-T., Kwak, J.-G., Sekharudu, C., Sundaralingam, M., Tsai, M.-D.
      (1991) Biochemistry 30: 11801

    Organizational Affiliation

    Department of Chemistry, Ohio State University, Columbus 43210.



Macromolecules
Find similar proteins by:  (by identity cutoff)  |  Structure
Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
PHOSPHOLIPASE A2A123Bos taurusMutation(s): 0 
Gene Names: PLA2G1B
EC: 3.1.1.4
UniProt
Find proteins for P00593 (Bos taurus)
Explore P00593 
Go to UniProtKB:  P00593
Protein Feature View
Expand
  • Reference Sequence
Small Molecules
Ligands 1 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
CA
Query on CA

Download Ideal Coordinates CCD File 
B [auth A]CALCIUM ION
Ca
BHPQYMZQTOCNFJ-UHFFFAOYSA-N
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.90 Å
  • R-Value Work: 0.185 
  • R-Value Observed: 0.185 
  • Space Group: P 31 2 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 46.11α = 90
b = 46.11β = 90
c = 102.1γ = 120
Software Package:
Software NamePurpose
X-PLORmodel building
X-PLORrefinement
X-PLORphasing

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 1995-02-07
    Type: Initial release
  • Version 1.1: 2008-03-24
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Version format compliance