title: Structural Basis for the Recognition of Eukaryotic Elongation Factor 2 Kinase by Calmodulin.
abstract: Binding of Ca(2+)-loaded calmodulin (CaM) activates eukaryotic elongation factor 2 kinase (eEF-2K) that phosphorylates eEF-2, its only known cellular target, leading to a decrease in global protein synthesis. Here, using an eEF-2K-derived peptide (eEF-2KCBD) that encodes the region necessary for its CaM-mediated activation, we provide a structural basis for their interaction. The striking feature of this association is the absence of Ca(2+) from the CaM C-lobe sites, even under high Ca(2+) conditions. eEF-2KCBD engages CaM largely through the C lobe of the latter in an anti-parallel 1-5-8 hydrophobic mode reinforced by a pair of unique electrostatic contacts. Sparse interactions of eEF-2KCBD with the CaM N lobe results in persisting inter-lobe mobility. A conserved eEF-2K residue (W85) anchors it to CaM by inserting into a deep hydrophobic cavity within the CaM C lobe. Mutation of this residue (W85S) substantially weakens interactions between full-length eEF-2K and CaM in vitro and reduces eEF-2 phosphorylation in cells.
authors: Department of Chemistry and Biochemistry, The City College of New York, New York, NY 10031, USA; Graduate Program in Biochemistry, The Graduate Center of CUNY, New York, NY 10016, USA.
authors: Kwangwoon
authors: K
authors: Lee
authors: Department of Chemistry and Biochemistry, The City College of New York, New York, NY 10031, USA.
authors: Sébastien
authors: S
authors: Alphonse
authors: Department of Chemistry and Biochemistry, The City College of New York, New York, NY 10031, USA.
authors: Andrea
authors: A
authors: Piserchio
authors: Graduate Program in Cell and Molecular Biology, University of Texas, Austin, TX 78712, USA.
authors: Clint D J
authors: CD
authors: Tavares
authors: Division of Chemical Biology and Medicinal Chemistry, University of Texas, Austin, TX 78712, USA.
authors: David H
authors: DH
authors: Giles
authors: Division of Chemical Biology and Medicinal Chemistry, University of Texas, Austin, TX 78712, USA.
authors: Rebecca M
authors: RM
authors: Wellmann
authors: Graduate Program in Cell and Molecular Biology, University of Texas, Austin, TX 78712, USA; Division of Chemical Biology and Medicinal Chemistry, University of Texas, Austin, TX 78712, USA.
authors: Kevin N
authors: KN
authors: Dalby
authors: Department of Chemistry and Biochemistry, The City College of New York, New York, NY 10031, USA; Graduate Program in Biochemistry, The Graduate Center of CUNY, New York, NY 10016, USA; Graduate Program in Chemistry, The Graduate Center of CUNY, New York, NY 10016, USA; Graduate Program in Physics, The Graduate Center of CUNY, New York, NY 10016, USA. Electronic address: rghose@ccny.cuny.edu.
authors: Ranajeet
authors: R
authors: Ghose
mesh_terms: D000595:Amino Acid Sequence; D001665:Binding Sites; D002118:Calcium / Q000737:chemistry* / Q000378:metabolism; D002147:Calmodulin / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D045744:Cell Line, Tumor; D018360:Crystallography, X-Ray; D054736:Elongation Factor 2 Kinase / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D004847:Epithelial Cells / Q000166:cytology / Q000378:metabolism; D015870:Gene Expression; D006801:Humans; D057927:Hydrophobic and Hydrophilic Interactions; D008958:Models, Molecular; D010445:Peptide Elongation Factors / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D010455:Peptides / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D010766:Phosphorylation; D011485:Protein Binding; D000072756:Protein Conformation, alpha-Helical; D054730:Protein Interaction Domains and Motifs; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D055672:Static Electricity; D013379:Substrate Specificity; D013816:Thermodynamics
chemical_list: D002147:Calmodulin; D010445:Peptide Elongation Factors; D010455:Peptides; D011994:Recombinant Proteins; C517689:EEF2K protein, human; D054736:Elongation Factor 2 Kinase; D002118:Calcium