Evolved to Be Active: Sulfate Ions Define Substrate Recognition Sites of Ck2alpha and Emphasise Its Exceptional Role Within the Cmgc Family of Eukaryotic Protein Kinases.
From: Universität zu Köln, Institut für Biochemie, Zülpicher Strasse 47, D-50674 Köln, Germany. Karsten.Niefind@uni-koeln.de
Journal of molecular biology
- Publish Date: Jul 2007
- ISSN: 0022-2836
- Volume: 370
- Issue: 3
- Pages: 427-38
- Medium: Print
- Language: English
- Citation (JAMA): Niefind Karsten, Yde Christina W, Ermakova Inessa, et al. Evolved to Be Active: Sulfate Ions Define Substrate Recognition Sites of Ck2alpha and Emphasise Its Exceptional Role Within the Cmgc Family of Eukaryotic Protein Kinases.. J. Mol. Biol. Jul 2007;370:427-38
Abstract
CK2alpha is the catalytic subunit of protein kinase CK2 and a member of the CMGC family of eukaryotic protein kinases like the cyclin-dependent kinases, the MAP kinases and glycogen-synthase kinase 3. We present here a 1.6 A resolution crystal structure of a fully active C-terminal deletion mutant of human CK2alpha liganded by two sulfate ions, and we compare this structure systematically with representative structures of related CMGC kinases. The two sulfate anions occupy binding pockets at the activation segment and provide the structural basis of the acidic consensus sequence S/T-D/E-X-D/E that governs substrate recognition by CK2. The anion binding sites are conserved among those CMGC kinases. In most cases they are neutralized by phosphorylation of a neighbouring threonine or tyrosine side-chain, which triggers conformational changes for regulatory purposes. CK2alpha, however, lacks both phosphorylation sites at the activation segment and structural plasticity. Here the anion binding sites are functionally changed from regulation to substrate recognition. These findings underline the exceptional role of CK2alpha as a constitutively active enzyme within a family of strictly controlled protein kinases.
Mesh Headings (Keywords): Amino Acid Sequence, Binding Sites, Casein Kinase II, Crystallography, X-Ray, Evolution, Molecular, Humans, Ions, Models, Molecular, Molecular Sequence Data, Protein Structure, Tertiary, Protein Subunits, Sequence Alignment, Substrate Specificity, Sulfates
Check for Full Text / PubMed Unique Identifier (PMID): 17524418
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