Nanodiscs allow phage display selection for ligands to non-linear epitopes on membrane proteins

PLoS One. 2013 Sep 9;8(9):e72272. doi: 10.1371/journal.pone.0072272. eCollection 2013.

Abstract

In this work, we exploited a method that uses polytopic membrane proteins as targets for phage display selections. Membrane proteins represent the largest class of drug targets and drug discovery is mostly based on the identification of ligands binding to target molecules. The screening of a phage display library for ligands against membrane proteins is typically hindered by the requirement of these proteins for a membrane environment, which is necessary to retain correct folding and epitope formation. Especially in proteins with multiple transmembrane domains, epitopes often are non-linear and consist of a combination of loops between transmembrane stretches of the proteins. Here, we have used bacteriorhodopsin (bR) as a model of polytopic membrane protein, assembled into nanoscale phospholipid bilayers, so called nanodiscs, to screen a phage display library for potential ligands. Nanodiscs provide a native-like environment to membrane proteins and thus selection of ligands can take place in a near physiological state. Screening a 12-mer phage display peptide library against bR nanodiscs led to the isolation of phage clones binding specifically to bR. We were further able to identify the binding site of selected phage clones proving that the clones bind to extramembranous, non-linear epitopes of bR. Thus, nanodiscs provide a suitable and general tool that allows screening of a phage display library against membrane proteins in a near native environment.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Bacteriorhodopsins / chemistry*
  • Binding Sites
  • Dimyristoylphosphatidylcholine / chemistry*
  • Epitope Mapping
  • Epitopes / chemistry
  • Ligands
  • Lipid Bilayers / chemistry
  • Membrane Proteins / chemistry
  • Molecular Sequence Data
  • Nanoparticles / chemistry*
  • Peptide Fragments / chemistry
  • Peptide Library
  • Protein Binding

Substances

  • Epitopes
  • Ligands
  • Lipid Bilayers
  • Membrane Proteins
  • Peptide Fragments
  • Peptide Library
  • Bacteriorhodopsins
  • Dimyristoylphosphatidylcholine

Grants and funding

MP was supported by a fellowship from the CLIB-Graduate Cluster Industrial Biotechnology. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.