Dissecting cAMP binding domain A in the R1α subunit of cAMP-dependent protein kinase: Distinct subsites for recognition of cAMP and the catalytic subunit

Lily Jun Shen Huang, Susan S. Taylor

Research output: Contribution to journalArticle

60 Scopus citations

Abstract

The two gene-duplicated cAMP binding domains in the regulatory subunits of cAMP dependent protein kinase are each comprised of an A helix, an eight- stranded β-barrel, and a B and C helix (1). The A domain is required for high affinity binding to C, while the B domain regulates access to the A domain. Using a combination of a yeast two-hybrid screen coupled with deletion analysis, cAMP binding domain A of R(I) was dissected into two structurally and functionally distinct subsites, one that binds cAMP and another that binds the C subunit. The minimum stable subdomain required for binding to C in the 1-3 micromolar range is composed of residues 94-169, while residues 236-244, mapped to the C helix of cAMP binding domain A, were defined as a second surface necessary for high affinity (5-10 nanomolar) binding to C. This portion of the C helix, due to its position directly between the two subsites, serves as a molecular switch for either a cAMP- bound conformation or a C-bound conformation and can thus modulate interactions of cAMP binding domain A with cAMP, with C, and with cAMP binding domain B.

Original languageEnglish (US)
Pages (from-to)26739-26746
Number of pages8
JournalJournal of Biological Chemistry
Volume273
Issue number41
DOIs
StatePublished - Oct 9 1998

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology

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