A protocol for identifying the binding sites of small molecules on the cystic fibrosis transmembrane conductance regulator (CFTR) protein

STAR Protoc. 2022 Apr 7;3(2):101258. doi: 10.1016/j.xpro.2022.101258. eCollection 2022 Jun 17.


We describe a protocol to identify the binding site(s) for a drug called ivacaftor that potentiates the CFTR chloride channel. We use photoaffinity probes-based on the structure of ivacaftor-to covalently modify the CFTR protein at the region that constitutes the drug binding site(s). We define the methods for photo-labeling CFTR, its membrane extraction, and enzymatic digestion using trypsin. We then describe the experimental methods to identify the modified peptides by using mass spectrometry. For complete details on the use and execution of this protocol, please refer to Laselva et al. (2021).

Keywords: Cell Biology; Cell Membrane; Cell-based Assays; Mass Spectrometry; Molecular/Chemical Probes; Protein Biochemistry.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Binding Sites
  • Cystic Fibrosis Transmembrane Conductance Regulator* / genetics
  • Cystic Fibrosis* / drug therapy
  • Humans
  • Ion Transport
  • Mutation


  • CFTR protein, human
  • Cystic Fibrosis Transmembrane Conductance Regulator

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