Crystal structure of the conserved N-terminal domain of the peroxisomal matrix protein import receptor, Pex14p

Proc Natl Acad Sci U S A. 2009 Jan 13;106(2):417-21. doi: 10.1073/pnas.0808681106. Epub 2009 Jan 2.

Abstract

Pex14p is a central component of the peroxisomal protein import machinery, in which the conserved N-terminal domain mediates dynamic interactions with other peroxins including Pex5p, Pex13p, and Pex19p. Here, we report the crystal structure of the conserved N-terminal domain of Pex14p with a three-helix bundle. A hydrophobic surface is composed of the conserved residues, of which two phenylalanine residues (Phe-35 and Phe-52) protrude to the solvent. Consequently, two putative binding pockets suitable for recognizing the helical WXXXF/Y motif of Pex5p are formed on the surface by the two phenylalanine residues accompanying with positively charged residues. The structural feature agrees well with our earlier findings where F35A/L36A and F52A/L53A mutants were impaired in the interactions with other peroxins such as Pex5p and Pex13p. Pex14p variants each with Phe-to-Ala mutation at positions 35, 52, and 35/52, respectively, were defective in restoring the impaired peroxisomal protein import in pex14 Chinese hamster ovary mutant ZP161 cells. Moreover, in GST pull-down assays His(6)-Pex5pL bound only to GST-Pex14p(25-70), not to any of GST-Pex14p(25-70)F35A, GST-Pex14p(25-70)F52A, and GST-Pex14p(25-70)F35A/F52A. Endogenous Pex5p was recruited to FLAG-Pex14p on peroxisomes in vivo but barely to FLAG-Pex14pF35A, FLAG-Pex14pF52A, and FLAG-Pex14pF35A/F52A. Collectively, Phe-35 and Phe-52 are essential for the Pex14p functions, including the interaction between Pex14p and Pex5p.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Binding Sites
  • Cloning, Molecular
  • Conserved Sequence
  • Crystallography, X-Ray
  • Hydrophobic and Hydrophilic Interactions
  • Ligands
  • Membrane Proteins / chemistry*
  • Peroxisome-Targeting Signal 1 Receptor
  • Protein Binding
  • Protein Interaction Mapping
  • Protein Structure, Tertiary
  • Rats
  • Receptors, Cytoplasmic and Nuclear / chemistry
  • Repressor Proteins / chemistry*
  • Solvents

Substances

  • Ligands
  • Membrane Proteins
  • Peroxisome-Targeting Signal 1 Receptor
  • Pex14 protein, rat
  • Receptors, Cytoplasmic and Nuclear
  • Repressor Proteins
  • Solvents

Associated data

  • PDB/3FF5