2A1L

Rat PITP-Beta Complexed to Phosphatidylcholine


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.18 Å
  • R-Value Free: 0.257 
  • R-Value Work: 0.210 

wwPDB Validation 3D Report Full Report


This is version 1.2 of the entry. See complete history

Literature

Structure of PITPbeta in Complex with Phosphatidylcholine: Comparison of Structure and Lipid Transfer to Other PITP Isoforms.

Vordtriede, P.B.Doan, C.N.Tremblay, J.M.Helmkamp, G.M.Yoder, M.D.

(2005) Biochemistry 44: 14760-14771

  • DOI: 10.1021/bi051191r

  • PubMed Abstract: 
  • Phosphatidylinositol transfer protein (PITP) is a ubiquitous eukaryotic protein that preferentially binds either phosphatidylinositol or phosphatidylcholine and catalyzes the exchange of these lipids between membranes. Mammalian cytosolic PITPs inclu ...

    Phosphatidylinositol transfer protein (PITP) is a ubiquitous eukaryotic protein that preferentially binds either phosphatidylinositol or phosphatidylcholine and catalyzes the exchange of these lipids between membranes. Mammalian cytosolic PITPs include the ubiquitously expressed PITPalpha and PITPbeta isoforms (269-270 residues). The crystal structure of rat PITPbeta complexed to dioleoylphosphatidylcholine was determined to 2.18 A resolution with molecular replacement using rat PITPalpha (77% sequence identify) as the phasing model. A structure comparison of the alpha and beta isoforms reveals minimal differences in protein conformation, differences in acyl conformation in the two isoforms, and remarkable conservation of solvent structure around the bound lipid. A comparison of transfer activity by human and rat PITPs, using small unilamellar vesicles with carefully controlled phospholipid composition, indicates that the beta isoforms have minimal differences in transfer preference between PtdIns and PtdCho when donor vesicles contain predominantly PtdCho. When PtdCho and PtdIns are present in equivalent concentrations in donor vesicles, PtdIns transfer occurs at approximately 3-fold the rate of PtdCho. The rat PITPbeta isoform clearly has the most diminished transfer rate of the four proteins studied. With the two rat isoforms, site-directed mutations of two locations within the lipid binding cavity that possess differing biochemical properties were characterized: I84alpha/F83beta and F225alpha/L224beta. The 225/224 locus is more critical in determining substrate specificity. Following the mutation of this locus to the other amino acid, the PtdCho transfer specific activity became PITPalpha (F225L) approximately PITPbeta and PITPbeta (L224F) approximately PITPalpha. The 225alpha/224beta locus plays a modest role in the specificity of both isoforms toward CerPCho.


    Organizational Affiliation

    Division of Cell Biology and Biophysics, University of Missouri-Kansas City, Kansas City, Missouri 64110-2499, USA.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Phosphatidylinositol transfer protein beta isoform
A
270Rattus norvegicusMutation(s): 0 
Gene Names: Pitpnb
Find proteins for P53812 (Rattus norvegicus)
Go to UniProtKB:  P53812
Small Molecules
Ligands 1 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
PCW
Query on PCW

Download SDF File 
Download CCD File 
A
1,2-DIOLEOYL-SN-GLYCERO-3-PHOSPHOCHOLINE
(Z,Z)-4-HYDROXY-N,N,N-TRIMETHYL-10-OXO-7-[(1-OXO-9-OCTADECENYL)OXY]-3,5,9-TRIOXA-4-PHOSPHAHEPTACOS-18-EN-1-AMINIUM-4-OXIDE
C44 H85 N O8 P
SNKAWJBJQDLSFF-NVKMUCNASA-O
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.18 Å
  • R-Value Free: 0.257 
  • R-Value Work: 0.210 
  • Space Group: P 43 21 2
Unit Cell:
Length (Å)Angle (°)
a = 65.945α = 90.00
b = 65.948β = 90.00
c = 133.513γ = 90.00
Software Package:
Software NamePurpose
HKL-2000data reduction
CNSrefinement
AMoREphasing
SCALEPACKdata scaling
HKL-2000data collection

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2005-11-29
    Type: Initial release
  • Version 1.1: 2008-04-30
    Type: Version format compliance
  • Version 1.2: 2011-07-13
    Type: Version format compliance