title: Neutron diffraction reveals hydrogen bonds critical for cGMP-selective activation: insights for cGMP-dependent protein kinase agonist design.
abstract: High selectivity of cyclic-nucleotide binding (CNB) domains for cAMP and cGMP are required for segregating signaling pathways; however, the mechanism of selectivity remains unclear. To investigate the mechanism of high selectivity in cGMP-dependent protein kinase (PKG), we determined a room-temperature joint X-ray/neutron (XN) structure of PKG Iβ CNB-B, a domain 200-fold selective for cGMP over cAMP, bound to cGMP (2.2 Å), and a low-temperature X-ray structure of CNB-B with cAMP (1.3 Å). The XN structure directly describes the hydrogen bonding interactions that modulate high selectivity for cGMP, while the structure with cAMP reveals that all these contacts are disrupted, explaining its low affinity for cAMP.
authors.affiliation: Verna and Mars McClean Department of Biochemistry and Molecular Biology, Baylor College of Medicine , One Baylor Plaza, Houston, Texas 77004, United States.
authors.forename: Gilbert Y
authors.initials: GY
authors.lastname: Huang
authors.forename: Oksana O
authors.initials: OO
authors.lastname: Gerlits
authors.forename: Matthew P
authors.initials: MP
authors.lastname: Blakeley
authors.forename: Banumathi
authors.initials: B
authors.lastname: Sankaran
authors.forename: Andrey Y
authors.initials: AY
authors.lastname: Kovalevsky
authors.forename: Choel
authors.initials: C
authors.lastname: Kim
mesh_terms: D000818:Animals; D000242:Cyclic AMP / Q000737:chemistry; D006152:Cyclic GMP / Q000737:chemistry; D062965:Cyclic GMP-Dependent Protein Kinase Type I / Q000737:chemistry*; D015195:Drug Design; D004789:Enzyme Activation; D020536:Enzyme Activators / Q000737:chemistry*; D006801:Humans; D006860:Hydrogen Bonding; D009502:Neutrons; D012542:Scattering, Radiation
chemical_list: D020536:Enzyme Activators; D000242:Cyclic AMP; D062965:Cyclic GMP-Dependent Protein Kinase Type I; C569718:PRKG1 protein, human; D006152:Cyclic GMP