Crystal structure of the catalytic subunit of protein kinase CK2 from Zea mays at 2.1 A resolution.
CK2alpha is the catalytic subunit of protein kinase CK2, an acidophilic and constitutively active eukaryotic Ser/Thr kinase involved in cell proliferation. A crystal structure, at 2.1 A resolution, of recombinant maize CK2alpha (rmCK2alpha) in the presence of ATP and Mg2+, shows the enzyme in an active conformation stabilized by interactions of the N-terminal region with the activation segment and with a cluster of basic residues known as the substrate recognition site. The close interaction between the N-terminal region and the activation segment is unique among known protein kinase structures and probably contributes to the constitutively active nature of CK2. The active centre is occupied by a partially disordered ATP molecule with the adenine base attached to a novel binding site of low specificity. This finding explains the observation that CK2, unlike other protein kinases, can use both ATP and GTP as phosphorylating agents.
Niefind
K
K
Universität zu Köln, Institut für Biochemie, Zülpicher Strasse 47, D-50674 Köln, Germany.
Guerra
B
B
Pinna
L A
LA
Issinger
O G
OG
Schomburg
D
D
D000255:Adenosine Triphosphate / Q000378:metabolism; D000595:Amino Acid Sequence; D001665:Binding Sites; D047390:Casein Kinase II; D018360:Crystallography, X-Ray; D006160:Guanosine Triphosphate / Q000378:metabolism; D046911:Macromolecular Substances; D008274:Magnesium / Q000378:metabolism; D008958:Models, Molecular; D008969:Molecular Sequence Data; D011487:Protein Conformation; D017346:Protein Serine-Threonine Kinases / Q000737:chemistry* / Q000378:metabolism; D017433:Protein Structure, Secondary; D011994:Recombinant Proteins / Q000737:chemistry / Q000378:metabolism; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D013379:Substrate Specificity; D003313:Zea mays / Q000201:enzymology*
D046911:Macromolecular Substances; D011994:Recombinant Proteins; D006160:Guanosine Triphosphate; D000255:Adenosine Triphosphate; D047390:Casein Kinase II; D017346:Protein Serine-Threonine Kinases; D008274:Magnesium