Disulfide bond structure and accessibility of cyteines in the ectodomain of the cholecystokinin receptor: Specific mono-reactive receptor constructs examine charge-sensitivity of loop regions

Xi Qin Ding, Vesile Dolu, Elizabeth M. Hadac, Michael Schuetz, Laurence J Miller

Research output: Contribution to journalArticle

11 Scopus citations


Cysteine residues play a unique role in structural analysis. We examined endogenous cysteine residues in the cholecystokinin receptor to determine participation in disulfide bonds and accessibility to methanethiosulfonate (MTS) reagents. Bonds linking Cys114 to Cys196 and Cys18 to Cys29 were demonstrated, with the first functionally important and the amino-terminal bond having no apparent function. Cys94, in the second transmembrane segment, was also accessible. Mutation of this residue to serine (C94S) was key for establishing a null cysteine-reactive pseudo - wild type receptor that could act as a template for insertion of a reactive cysteine (N102C, A204C, and T341C). Modification of T341C with a negatively charged MTS reagent reduced CCK agonist binding, while this binding was enhanced by a positively charged MTS reagent. This pattern was repeated in mutants having the same residue directly replaced with a charged residue.

Original languageEnglish (US)
Pages (from-to)83-91
Number of pages9
JournalReceptors and Channels
Issue number2
StatePublished - 2003



  • Cholecystokinin receptor
  • Cysteine accessibility
  • Disulfide bonds
  • G protein-coupled receptor

ASJC Scopus subject areas

  • Clinical Biochemistry
  • Endocrinology
  • Cell Biology

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