title: 14-3-3 protein C-terminal stretch occupies ligand binding groove and is displaced by phosphopeptide binding.
abstract: 14-3-3 proteins are important regulators of numerous cellular signaling circuits. They bind to phosphorylated protein ligands and regulate their functions by a number of different mechanisms. The C-terminal part of the 14-3-3 protein is known to be involved in the regulation of 14-3-3 binding properties. The structure of this region is unknown; however, a possible location of the C-terminal stretch within the ligand binding groove of the 14-3-3 protein has been suggested. To fully understand the role of the C-terminal stretch in the regulation of the 14-3-3 protein binding properties, we investigated the physical location of the C-terminal stretch and its changes upon the ligand binding. For this purpose, we have used Forster resonance energy transfer (FRET) measurements and molecular dynamics simulation. FRET measurements between Trp242 located at the end of the C-terminal stretch and a dansyl group attached at two different cysteine residues (Cys25 or Cys189) indicated that in the absence of the ligand, the C-terminal stretch occupies the ligand binding groove of 14-3-3 protein. Our data also showed that phosphopeptide binding displaces the C-terminal stretch from the ligand binding groove. Intramolecular distances calculated from FRET measurements fit well with distances obtained from molecular dynamics simulation of full-length 14-3-3zeta protein.
authors.affiliation: Department of Physical and Macromolecular Chemistry, Faculty of Science, Charles University, Prague 12843, Czech Republic.
authors.forename: Jan
authors.initials: J
authors.lastname: Silhan
authors.forename: Veronika
authors.initials: V
authors.lastname: Obsilova
authors.forename: Jaroslav
authors.initials: J
authors.lastname: Vecer
authors.forename: Petr
authors.initials: P
authors.lastname: Herman
authors.forename: Miroslav
authors.initials: M
authors.lastname: Sulc
authors.forename: Jan
authors.initials: J
authors.lastname: Teisinger
authors.forename: Tomas
authors.initials: T
authors.lastname: Obsil
mesh_terms: D048948:14-3-3 Proteins / Q000737:chemistry* / Q000378:metabolism; D018360:Crystallography, X-Ray; D003545:Cysteine / Q000737:chemistry; D004305:Dose-Response Relationship, Drug; D031541:Fluorescence Resonance Energy Transfer; D006801:Humans; D007700:Kinetics; D008024:Ligands; D013058:Mass Spectrometry; D008958:Models, Molecular; D015233:Models, Statistical; D009154:Mutation; D010455:Peptides / Q000737:chemistry; D010748:Phosphopeptides / Q000737:chemistry*; D011485:Protein Binding; D011487:Protein Conformation; D017434:Protein Structure, Tertiary; D013997:Time Factors; D014364:Tryptophan / Q000737:chemistry
chemical_list: D048948:14-3-3 Proteins; D008024:Ligands; D010455:Peptides; D010748:Phosphopeptides; D014364:Tryptophan; D003545:Cysteine