A designed buried salt bridge modulates heterodimerization of a membrane peptide

Sandip Shinde, Jennifer K. Binder, Bhupesh Goyal, B. Woodrum, Sonia De Munari, Marcia Levitus, Giovanna Ghirlanda

Research output: Contribution to journalArticlepeer-review


Specific helix-helix interactions underpin the correct assembly of multipass membrane proteins. Here, we show that a designed buried salt bridge mediates heterodimer formation of model transmembrane helical peptides in a pH-dependent manner. The model peptides bear side chains functionalized with either a carboxylic acid or a primary amine within a hydrophobic segment. The association behavior was monitored by Forster resonance energy transfer, revealing that heterodimer formation is maximized at a pH close to neutrality (pH 6.5), at which each peptide is found in a charged state. In contrast, heterodimerization is disfavored at low and high values of pH, because either the carboxylic acid or the primary amine is present in its neutral state, thus preventing the formation of a salt bridge. These findings provide a blueprint for the design and modulation of protein-protein interactions in membrane proteins.

Original languageEnglish (US)
Pages (from-to)437-443
Number of pages7
JournalBiopolymers - Peptide Science Section
Issue number6
StatePublished - Nov 1 2014


  • Dimerization
  • Förster resonance energy transfer
  • Heterodimer
  • Membrane protein
  • Micelles

ASJC Scopus subject areas

  • Biophysics
  • Biochemistry
  • Biomaterials
  • Organic Chemistry


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