Inclining the purine base binding plane in protein kinase CK2 by exchanging the flanking side-chains generates a preference for ATP as a cosubstrateYde, C.W., Ermakova, I., Issinger, O.-G., Niefind, K.
(2005) J.Mol.Biol. 347: 399-414
- PubMed: 15740749
- DOI: 10.1016/j.jmb.2005.01.003
- Primary Citation of Related Structures:
- Also Cited By: 5N9N, 5N9L, 5N9K, 3U9C, 3U87, 3FWQ, 3BW5
- PubMed Abstract:
- The CK2 alpha/CK2 beta interface of human protein kinase CK2 harbors a binding pocket for small molecules
Raaf, J.,Brunstein, E.,Issinger, O.-G.,Niefind, K.
(2008) Chem.Biol. 15: 111
- Protein kinase CK2 in health and disease: Protein kinase CK2: from structures to insights
Niefind, K.,Raaf, J.,Issinger, O.-G.
(2009) Cell.Mol.Life Sci. 66: 1800
- Conformational plasticity of the catalytic subunit of protein kinase CK2 and its consequences for regulation and drug design
Niefind, K.,Issinger, O.-G.
(2010) Biochim.Biophys.Acta 1804: 484
Protein kinase CK2 (casein kinase 2) is a highly conserved and ubiquitously found eukaryotic serine/threonine kinase that plays a role in various cellular key processes like proliferation, apoptosis and circadian rhythm. One of its prominent biochemi ...
Protein kinase CK2 (casein kinase 2) is a highly conserved and ubiquitously found eukaryotic serine/threonine kinase that plays a role in various cellular key processes like proliferation, apoptosis and circadian rhythm. One of its prominent biochemical properties is its ability to use GTP as well as ATP as a cosubstrate (dual-cosubstrate specificity). This feature is exceptional among eukaryotic protein kinases, and its biological significance is unknown. We describe here a mutant of the catalytic subunit of protein kinase CK2 (CK2alpha) from Homo sapiens (hsCK2alpha) with a clear and CK2-atypical preference for ATP compared to GTP. This mutant was designed on the basis of several structures of CK2alpha from Zea mays (zmCK2alpha) in complex with various ATP-competitive ligands. A structural overlay revealed the existence of a "purine base binding plane" harbouring the planar moiety of the respective ligand like the purine base of ATP and GTP. This purine base binding plane is sandwiched between the side-chains of Ile66 (Val66 in hsCK2alpha) and Met163, and it adopts a significantly different orientation than in prominent homologues like cAMP-dependent protein kinase (CAPK). By exchanging these two flanking amino acids (Val66Ala, Met163Leu) in hsCK2alpha(1-335), a C-terminally truncated variant of hsCK2alpha, the cosubstrate specificity shifted in the expected direction so that the mutant strongly favours ATP. A structure determination of the mutant in complex with an ATP-analogue confirmed the predicted change of the purine base binding plane orientation. An unexpected but in retrospect plausible consequence of the mutagenesis was, that the helix alpha D region, which is in the direct neighbourhood of the ATP-binding site, has adopted a conformation that is more similar to CAPK and less favourable for binding of GTP. These findings demonstrate that CK2alpha possesses sophisticated structural adaptations in favour of dual-cosubstrate specificity, suggesting that this property could be of biological significance.
Syddansk Universitet, Institut for Biokemi og Molekylaerbiologi, Campusvej 55, DK-5230 Odense, Denmark.