3bw5

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==Overview==
==Overview==
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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.
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The Ser/Thr kinase CK2 (previously called casein kinase 2) is composed of two catalytic chains (CK2alpha) attached to a dimer of noncatalytic subunits (CK2beta). CK2 is involved in suppression of apoptosis, cell survival, and tumorigenesis. To investigate these activities and possibly affect them, selective CK2 inhibitors are required. An often-used CK2 inhibitor is 5,6-dichloro-1-beta-D-ribofuranosylbenzimidazole (DRB). In a complex structure with human CK2alpha, DRB binds to the canonical ATP cleft, but additionally it occupies an allosteric site that can be alternatively filled by glycerol. Inhibition kinetic studies corroborate the dual binding mode of the inhibitor. Structural comparisons reveal a surprising conformational plasticity of human CK2alpha around both DRB binding sites. After local rearrangement, the allosteric site serves as a CK2beta interface. This opens the potential to construct molecules interfering with the CK2alpha/CK2beta interaction.
==About this Structure==
==About this Structure==
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3BW5 is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Homo_sapiens Homo sapiens] with <scene name='pdbligand=CL:'>CL</scene>, <scene name='pdbligand=ANP:'>ANP</scene> and <scene name='pdbligand=GOL:'>GOL</scene> as [http://en.wikipedia.org/wiki/ligands ligands]. This structure supersedes the now removed PDB entry 1YMI. Active as [http://en.wikipedia.org/wiki/Non-specific_serine/threonine_protein_kinase Non-specific serine/threonine protein kinase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=2.7.11.1 2.7.11.1] Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=3BW5 OCA].
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3BW5 is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Homo_sapiens Homo sapiens] with <scene name='pdbligand=CL:'>CL</scene>, <scene name='pdbligand=ANP:'>ANP</scene> and <scene name='pdbligand=GOL:'>GOL</scene> as [http://en.wikipedia.org/wiki/ligands ligands]. This structure supersedes the now removed PDB entry 1YMI. Active as [http://en.wikipedia.org/wiki/Non-specific_serine/threonine_protein_kinase Non-specific serine/threonine protein kinase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=2.7.11.1 2.7.11.1] Known structural/functional Sites: <scene name='pdbsite=AC1:Cl+Binding+Site+For+Residue+A+336'>AC1</scene>, <scene name='pdbsite=AC2:Anp+Binding+Site+For+Residue+A+340'>AC2</scene> and <scene name='pdbsite=AC3:Gol+Binding+Site+For+Residue+A+341'>AC3</scene>. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=3BW5 OCA].
==Reference==
==Reference==
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Inclining the purine base binding plane in protein kinase CK2 by exchanging the flanking side-chains generates a preference for ATP as a cosubstrate., Yde CW, Ermakova I, Issinger OG, Niefind K, J Mol Biol. 2005 Mar 25;347(2):399-414. Epub 2005 Jan 18. PMID:[http://ispc.weizmann.ac.il//pmbin/getpm?pmid=15740749 15740749]
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The CK2alpha/CK2beta Interface of Human Protein Kinase CK2 Harbors a Binding Pocket for Small Molecules., Raaf J, Brunstein E, Issinger OG, Niefind K, Chem Biol. 2008 Feb;15(2):111-7. PMID:[http://ispc.weizmann.ac.il//pmbin/getpm?pmid=18291315 18291315]
[[Category: Homo sapiens]]
[[Category: Homo sapiens]]
[[Category: Non-specific serine/threonine protein kinase]]
[[Category: Non-specific serine/threonine protein kinase]]
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[[Category: wnt signaling pathway]]
[[Category: wnt signaling pathway]]
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''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Wed Mar 5 13:26:19 2008''

Revision as of 11:26, 5 March 2008


3bw5, resolution 1.66Å

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Crystal structure of a mutant of human protein kinase CK2alpha with altered cosubstrate specificity

Overview

The Ser/Thr kinase CK2 (previously called casein kinase 2) is composed of two catalytic chains (CK2alpha) attached to a dimer of noncatalytic subunits (CK2beta). CK2 is involved in suppression of apoptosis, cell survival, and tumorigenesis. To investigate these activities and possibly affect them, selective CK2 inhibitors are required. An often-used CK2 inhibitor is 5,6-dichloro-1-beta-D-ribofuranosylbenzimidazole (DRB). In a complex structure with human CK2alpha, DRB binds to the canonical ATP cleft, but additionally it occupies an allosteric site that can be alternatively filled by glycerol. Inhibition kinetic studies corroborate the dual binding mode of the inhibitor. Structural comparisons reveal a surprising conformational plasticity of human CK2alpha around both DRB binding sites. After local rearrangement, the allosteric site serves as a CK2beta interface. This opens the potential to construct molecules interfering with the CK2alpha/CK2beta interaction.

About this Structure

3BW5 is a Single protein structure of sequence from Homo sapiens with , and as ligands. This structure supersedes the now removed PDB entry 1YMI. Active as Non-specific serine/threonine protein kinase, with EC number 2.7.11.1 Known structural/functional Sites: , and . Full crystallographic information is available from OCA.

Reference

The CK2alpha/CK2beta Interface of Human Protein Kinase CK2 Harbors a Binding Pocket for Small Molecules., Raaf J, Brunstein E, Issinger OG, Niefind K, Chem Biol. 2008 Feb;15(2):111-7. PMID:18291315

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