3EED

Crystal structure of human protein kinase CK2 regulatory subunit (CK2beta; mutant 1-193)

Summary for 3EED

• Entry DOI: 10.2210/pdb3eed/pdb
• Related: 1JWH 1QF8 1RQF
• Descriptor: Casein kinase II subunit beta, ZINC ION, SULFATE ION, ... (4 entities in total)
• Functional Keywords: protein kinase ck2, casein kinase 2, casein kinase ii, eukaryotic protein kinases, phosphoprotein, wnt signaling pathway, transferase
• Biological source: Homo sapiens (human)
• Total number of polymer chains: 2
• Total formula weight: 45403.98

Authors

Niefind, K.,Raaf, J.,Issinger, O.-G. (deposition date: 2008-09-04, release date: 2008-09-16, Last modification date: 2023-11-01)

Primary citation

Raaf, J.,Brunstein, E.,Issinger, O.-G.,Niefind, K.
The interaction of CK2{alpha} and CK2{beta}, the subunits of protein kinase CK2, requires CK2{beta} in a preformed conformation and is enthalpically driven
Protein Sci., 17:2180-2186, 2008

PubMed Abstract: The protein kinase CK2 (former name: "casein kinase 2") predominantly occurs as a heterotetrameric holoenzyme composed of two catalytic chains (CK2alpha) and two noncatalytic subunits (CK2beta). The CK2beta subunits form a stable dimer to which the CK2alpha monomers are attached independently. In contrast to the cyclins in the case of the cyclin-dependent kinases CK2beta is no on-switch of CK2alpha; rather the formation of the CK2 holoenzyme is accompanied with an overall change of the enzyme's profile including a modulation of the substrate specificity, an increase of the thermostability, and an allocation of docking sites for membranes and other proteins. In this study we used C-terminal deletion variants of human CK2alpha and CK2beta that were enzymologically fully competent and in particular able to form a heterotetrameric holoenzyme. With differential scanning calorimetry (DSC) we confirmed the strong thermostabilization effect of CK2alpha on CK2beta with an upshift of the CK2alpha melting temperature of more than 9 degrees . Using isothermal titration calorimetry (ITC) we measured a dissociation constant of 12.6 nM. This high affinity between CK2alpha and CK2beta is mainly caused by enthalpic rather than entropic contributions. Finally, we determined a crystal structure of the CK2beta construct to 2.8 A resolution and revealed by structural comparisons with the CK2 holoenzyme structure that the CK2beta conformation is largely conserved upon association with CK2alpha, whereas the latter undergoes significant structural adaptations of its backbone.

PubMed: 18824508
DOI: 10.1110/ps.037770.108

Experimental method

X-RAY DIFFRACTION (2.8 Å)