An arginine ladder in OprP mediates phosphate-specific transfer across the outer membrane

Nat Struct Mol Biol. 2007 Jan;14(1):85-7. doi: 10.1038/nsmb1189. Epub 2006 Dec 24.


The outer membrane protein OprP mediates the transport of essential phosphate anions into the pathogenic bacterium Pseudomonas aeruginosa. Here we report the crystallographic structure of trimeric OprP at 1.9-A resolution, revealing an unprecedented 9-residue arginine 'ladder' that spans from the extracellular surface down through a constriction zone where phosphate is coordinated. Lysine residues coat the inner periplasmic surface, creating an 'electropositive sink' that pulls the phosphates through the eyelet and into the cell.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Arginine
  • Bacterial Proteins / chemistry*
  • Bacterial Proteins / metabolism*
  • Cell Membrane / metabolism*
  • Crystallography, X-Ray
  • Ion Transport
  • Phosphates / metabolism*
  • Porins / chemistry*
  • Porins / metabolism*
  • Protein Conformation
  • Protein Structure, Secondary
  • Protein Structure, Tertiary
  • Pseudomonas aeruginosa / chemistry*
  • Pseudomonas aeruginosa / metabolism


  • Bacterial Proteins
  • Phosphates
  • Porins
  • oprP protein, Pseudomonas aeruginosa
  • Arginine

Associated data

  • PDB/2O4V