1C74

Structure of the double mutant (K53,56M) of phospholipase A2


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.9 Å
  • R-Value Free: 0.224 
  • R-Value Work: 0.189 

wwPDB Validation 3D Report Full Report


This is version 1.2 of the entry. See complete history

Literature

Structural basis of the anionic interface preference and k*cat activation of pancreatic phospholipase A2.

Yu, B.Z.Poi, M.J.Ramagopal, U.A.Jain, R.Ramakumar, S.Berg, O.G.Tsai, M.D.Sekar, K.Jain, M.K.

(2000) Biochemistry 39: 12312-12323


  • PubMed Abstract: 
  • Pancreatic phospholipase A(2) (PLA2) shows a strong preference for the binding to the anionic interface and a consequent allosteric activation. In this paper, we show that virtually all the preference is mediated through 3 (Lys-53, -56, and -120) of ...

    Pancreatic phospholipase A(2) (PLA2) shows a strong preference for the binding to the anionic interface and a consequent allosteric activation. In this paper, we show that virtually all the preference is mediated through 3 (Lys-53, -56, and -120) of the 12 cationic residues of bovine pancreatic PLA2. The lysine-to-methionine substitution enhances the binding of the enzyme to the zwitterionic interface, and for the K53,56,120M triple mutant at the zwitterionic interface is comparable to that for the wild type (WT) at the anionic interface. In the isomorphous crystal structure, the backbone folding of K53,56M K120,121A and WT are virtually identical, yet a significant change in the side chains of certain residues, away from the site of substitution, mostly at the putative contact site with the interface (i-face), is discernible. Such reciprocity, also supported by the spectroscopic results for the free and bound forms of the enzyme, is expected because a distal structural change that perturbs the interfacial binding could also affect the i-face. The results show that lysine-to-methionine substitution induces a structural change that promotes the binding of PLA2 to the interface as well as the substrate binding to the enzyme at the interface. The kinetic results are consistent with a model in which the interfacial Michaelis complex exists in two forms, and the complex that undergoes the chemical step is formed by the charge compensation of Lys-53 and -56. Analysis of the incremental changes in the kinetic parameters shows that the charge compensation of Lys-53 and -56 contributes to the activation and that of Lys-120 contributes only to the structural change that promotes the stability of the Michaelis complex at the interface. The charge compensation effects on these three residues also account for the differences in the anionic interface preference of the evolutionarily divergent secreted PLA2.


    Organizational Affiliation

    Department of Chemistry and Biochemistry, University of Delaware, Newark, Delaware 19716, USA.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
PHOSPHOLIPASE A2
A
123Bos taurusGene Names: PLA2G1B
EC: 3.1.1.4
Find proteins for P00593 (Bos taurus)
Go to Gene View: PLA2G1B
Go to UniProtKB:  P00593
Small Molecules
Ligands 1 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
CA
Query on CA

Download SDF File 
Download CCD File 
A
CALCIUM ION
Ca
BHPQYMZQTOCNFJ-UHFFFAOYSA-N
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.9 Å
  • R-Value Free: 0.224 
  • R-Value Work: 0.189 
  • Space Group: P 31 2 1
Unit Cell:
Length (Å)Angle (°)
a = 46.410α = 90.00
b = 46.410β = 90.00
c = 102.720γ = 120.00
Software Package:
Software NamePurpose
X-PLORmodel building
DENZOdata reduction
X-PLORrefinement
SCALEPACKdata scaling
X-PLORphasing

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2000-07-22
    Type: Initial release
  • Version 1.1: 2008-04-26
    Type: Version format compliance
  • Version 1.2: 2011-07-13
    Type: Version format compliance