Structural characterization of the rod cGMP phosphodiesterase 6

J Mol Biol. 2010 Aug 20;401(3):363-73. doi: 10.1016/j.jmb.2010.06.044. Epub 2010 Jul 1.


Rod cGMP phosphodiesterase 6 (PDE6) is a key enzyme of the phototransduction cascade, consisting of PDE6alpha, PDE6beta, and two regulatory PDE6gamma subunits. PDE6 is membrane associated through isoprenyl membrane anchors attached to the C-termini of PDE6alpha and PDE6beta and can form a complex with prenyl-binding protein delta (PrBP/delta), an isoprenyl-binding protein that is highly expressed in photoreceptors. The stoichiometry of PDE6-PrBP/delta binding and the mechanism by which the PDE6-PrBP/delta complex assembles have not been fully characterized, and the location of regulatory PDE6gamma subunits within the protein assembly has not been elucidated. To clarify these questions, we have developed a rapid purification method for PDE6-PrBP/delta from bovine rod outer segments utilizing recombinant PrBP/delta. Transmission electron microscopy of negatively stained samples revealed the location of PrBP/delta and, thus, where the carboxyl-termini of PDE6alpha and PDE6beta must be located. The three-dimensional structure of the PDE6alphabetagamma complex was determined up to 18 A resolution from single-particle projections and was interpreted by model building to identify the probable location of isoprenylation, PDE6gamma subunits, and catalytic sites.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Catalytic Domain
  • Cattle
  • Cyclic GMP
  • Cyclic Nucleotide Phosphodiesterases, Type 6 / chemistry*
  • Cyclic Nucleotide Phosphodiesterases, Type 6 / isolation & purification*
  • Microscopy, Electron, Transmission
  • Models, Molecular
  • Peptide Fragments / chemistry
  • Prenylation
  • Protein Conformation
  • Protein Subunits
  • Rod Cell Outer Segment / enzymology*


  • Peptide Fragments
  • Protein Subunits
  • Cyclic Nucleotide Phosphodiesterases, Type 6
  • Cyclic GMP

Associated data

  • PDB/3DBA
  • PDB/3JWQ
  • PDB/3LBJ