Structural Basis of Cyclic Nucleotide Selectivity in cGMP-dependent Protein Kinase II

J Biol Chem. 2016 Mar 11;291(11):5623-5633. doi: 10.1074/jbc.M115.691303. Epub 2016 Jan 14.


Membrane-bound cGMP-dependent protein kinase (PKG) II is a key regulator of bone growth, renin secretion, and memory formation. Despite its crucial physiological roles, little is known about its cyclic nucleotide selectivity mechanism due to a lack of structural information. Here, we find that the C-terminal cyclic nucleotide binding (CNB-B) domain of PKG II binds cGMP with higher affinity and selectivity when compared with its N-terminal CNB (CNB-A) domain. To understand the structural basis of cGMP selectivity, we solved co-crystal structures of the CNB domains with cyclic nucleotides. Our structures combined with mutagenesis demonstrate that the guanine-specific contacts at Asp-412 and Arg-415 of the αC-helix of CNB-B are crucial for cGMP selectivity and activation of PKG II. Structural comparison with the cGMP selective CNB domains of human PKG I and Plasmodium falciparum PKG (PfPKG) shows different contacts with the guanine moiety, revealing a unique cGMP selectivity mechanism for PKG II.

Keywords: NO-cGMP signaling; X-ray crystallography; allosteric regulation; cGMP-dependent protein kinase; cyclic nucleotide; cyclic nucleotide-binding domain (CNB); ligand-binding protein; protein kinase G (PKG); receptor structure-function; second messenger; serine/threonine protein kinase.

Publication types

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

MeSH terms

  • Allosteric Regulation
  • Animals
  • COS Cells
  • Chlorocebus aethiops
  • Crystallography, X-Ray
  • Cyclic AMP / metabolism
  • Cyclic GMP / metabolism*
  • Cyclic GMP-Dependent Protein Kinase Type II / chemistry*
  • Cyclic GMP-Dependent Protein Kinase Type II / metabolism*
  • HEK293 Cells
  • Humans
  • Models, Molecular
  • Protein Structure, Tertiary
  • Substrate Specificity


  • Cyclic AMP
  • Cyclic GMP-Dependent Protein Kinase Type II
  • Cyclic GMP

Associated data

  • PDB/3OCP
  • PDB/4KU7
  • PDB/5C6C