Activation of PKA via asymmetric allosteric coupling of structurally conserved cyclic nucleotide binding domains

Nat Commun. 2019 Sep 4;10(1):3984. doi: 10.1038/s41467-019-11930-2.


Cyclic nucleotide-binding (CNB) domains allosterically regulate the activity of proteins with diverse functions, but the mechanisms that enable the cyclic nucleotide-binding signal to regulate distant domains are not well understood. Here we use optical tweezers and molecular dynamics to dissect changes in folding energy landscape associated with cAMP-binding signals transduced between the two CNB domains of protein kinase A (PKA). We find that the response of the energy landscape upon cAMP binding is domain specific, resulting in unique but mutually coordinated tasks: one CNB domain initiates cAMP binding and cooperativity, whereas the other triggers inter-domain interactions that promote the active conformation. Inter-domain interactions occur in a stepwise manner, beginning in intermediate-liganded states between apo and cAMP-bound domains. Moreover, we identify a cAMP-responsive switch, the N3A motif, whose conformation and stability depend on cAMP occupancy. This switch serves as a signaling hub, amplifying cAMP-binding signals during PKA activation.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Algorithms
  • Allosteric Regulation*
  • Allosteric Site
  • Animals
  • Binding Sites
  • Catalytic Domain*
  • Cattle
  • Cyclic AMP / chemistry
  • Cyclic AMP / metabolism*
  • Cyclic AMP-Dependent Protein Kinases / chemistry
  • Cyclic AMP-Dependent Protein Kinases / genetics
  • Cyclic AMP-Dependent Protein Kinases / metabolism*
  • Enzyme Activation
  • Molecular Dynamics Simulation
  • Optical Tweezers
  • Protein Binding
  • Signal Transduction*


  • Cyclic AMP
  • Cyclic AMP-Dependent Protein Kinases