title: Synchronous opening and closing motions are essential for cAMP-dependent protein kinase A signaling.
abstract: Conformational fluctuations play a central role in enzymatic catalysis. However, it is not clear how the rates and the coordination of the motions affect the different catalytic steps. Here, we used NMR spectroscopy to analyze the conformational fluctuations of the catalytic subunit of the cAMP-dependent protein kinase (PKA-C), a ubiquitous enzyme involved in a myriad of cell signaling events. We found that the wild-type enzyme undergoes synchronous motions involving several structural elements located in the small lobe of the kinase, which is responsible for nucleotide binding and release. In contrast, a mutation (Y204A) located far from the active site desynchronizes the opening and closing of the active cleft without changing the enzyme's structure, rendering it catalytically inefficient. Since the opening and closing motions govern the rate-determining product release, we conclude that optimal and coherent conformational fluctuations are necessary for efficient turnover of protein kinases.
authors.affiliation: Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, MN 55455, USA.
authors.forename: Atul K
authors.initials: AK
authors.lastname: Srivastava
authors.affiliation: Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, MN 55455, USA.
authors.forename: Leanna R
authors.initials: LR
authors.lastname: McDonald
authors.affiliation: Department of Chemistry, University of Minnesota, Minneapolis, MN 55455, USA.
authors.forename: Alessandro
authors.initials: A
authors.lastname: Cembran
authors.affiliation: Department of Chemistry, University of Minnesota, Minneapolis, MN 55455, USA.
authors.forename: Jonggul
authors.initials: J
authors.lastname: Kim
authors.affiliation: Department of Chemistry, University of Minnesota, Minneapolis, MN 55455, USA.
authors.forename: Larry R
authors.initials: LR
authors.lastname: Masterson
authors.affiliation: Department of Chemistry and Biochemistry, University of California at San Diego, La Jolla, CA 92093, USA.
authors.forename: Christopher L
authors.initials: CL
authors.lastname: McClendon
authors.affiliation: Department of Chemistry and Biochemistry, University of California at San Diego, La Jolla, CA 92093, USA.
authors.forename: Susan S
authors.initials: SS
authors.lastname: Taylor
authors.affiliation: Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, MN 55455, USA; Department of Chemistry, University of Minnesota, Minneapolis, MN 55455, USA. Electronic address: vegli001@umn.edu.
authors.forename: Gianluigi
authors.initials: G
authors.lastname: Veglia
mesh_terms: D000595:Amino Acid Sequence; D002384:Catalysis; D000242:Cyclic AMP / Q000378:metabolism*; D017868:Cyclic AMP-Dependent Protein Kinases / Q000378:metabolism*; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D011485:Protein Binding; D011487:Protein Conformation; D015398:Signal Transduction / Q000502:physiology*
chemical_list: D000242:Cyclic AMP; D017868:Cyclic AMP-Dependent Protein Kinases