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Probing Subunits Interactions in KATP Channels Using Photo-Crosslinking via Genetically Encoded p-Azido-l-phenylalanine

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Part of the Methods in Molecular Biology book series (MIMB,volume 1684)


Potassium channels are multimeric protein complexes regulated by diverse physiological and pharmacological ligands. The key to understanding mechanisms of channel regulation is the ability to detect structural changes associated with ligand binding. While high-resolution structural methods such as X-ray crystallography and single-particle cryo-electron microscopy offer direct visualization of channel structures, these methods do have limitations and may not be suitable for the question of interest. In this chapter, we describe the use of a photo-cross-linker unnatural amino acid, p-azido-l-phenylalanine, to probe interactions between two proteins, the sulfonylurea receptor 1 and the inwardly rectifying potassium channel Kir6.2, that form the ATP-sensitive potassium (KATP) channel complex in the absence or presence of ligands. The difference in the extent of crosslinking between a liganded state and unliganded state can be used as a readout of ligand-induced structural changes. We anticipate that the protocol described here will also be applicable for other potassium channels and protein complexes.

Key words

  • Sulfonylurea receptor
  • Kir6.2
  • Azidophenylalanine
  • Glibenclamide
  • Carbamazepine
  • Membrane protein
  • Pharmacological chaperone

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We are grateful to Dr. Thomas Sakmar for the suppressor tRNA plasmid and the plasmid of tRNA synthetase specific for p-azido-l-phenylalanine, and for valuable advice. This work was supported by National Institutes of Health grant R01DK066485.

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Correspondence to Show-Ling Shyng .

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Devaraneni, P., Rex, E.A., Shyng, SL. (2018). Probing Subunits Interactions in KATP Channels Using Photo-Crosslinking via Genetically Encoded p-Azido-l-phenylalanine. In: Shyng, SL., Valiyaveetil, F., Whorton, M. (eds) Potassium Channels. Methods in Molecular Biology, vol 1684. Humana Press, New York, NY.

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  • Print ISBN: 978-1-4939-7361-3

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