Engineering a rigid protein tunnel for biomolecular detection

Mohammad M. Mohammad, Raghuvaran Iyer, Khalil R. Howard, Mark P. McPike, Philip N. Borer, Liviu Movileanu

Research output: Contribution to journalArticlepeer-review

105 Scopus citations


One intimidating challenge in protein nanopore-based technologies is designing robust protein scaffolds that remain functionally intact under a broad spectrum of detection conditions. Here, we show that an extensively engineered bacterial ferric hydroxamate uptake component A (FhuA), a β-barrel membrane protein, functions as a robust protein tunnel for the sampling of biomolecular events. The key implementation in this work was the coupling of direct genetic engineering with a refolding approach to produce an unusually stable protein nanopore. More importantly, this nanostructure maintained its stability under many experimental circumstances, some of which, including low ion concentration and highly acidic aqueous phase, are normally employed to gate, destabilize, or unfold β-barrel membrane proteins. To demonstrate these advantageous traits, we show that the engineered FhuA-based protein nanopore functioned as a sensing element for examining the proteolytic activity of an enzyme at highly acidic pH and for determining the kinetics of protein-DNA aptamer interactions at physiological salt concentration.

Original languageEnglish (US)
Pages (from-to)9521-9531
Number of pages11
JournalJournal of the American Chemical Society
Issue number22
StatePublished - Jun 6 2012

ASJC Scopus subject areas

  • Catalysis
  • General Chemistry
  • Biochemistry
  • Colloid and Surface Chemistry


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