1lp4: Difference between revisions
New page: left|200px<br /><applet load="1lp4" size="450" color="white" frame="true" align="right" spinBox="true" caption="1lp4, resolution 1.86Å" /> '''Crystal structure of... |
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[[Image:1lp4.jpg|left|200px]]<br /><applet load="1lp4" size=" | [[Image:1lp4.jpg|left|200px]]<br /><applet load="1lp4" size="350" color="white" frame="true" align="right" spinBox="true" | ||
caption="1lp4, resolution 1.86Å" /> | caption="1lp4, resolution 1.86Å" /> | ||
'''Crystal structure of a binary complex of the catalytic subunit of protein kinase CK2 with Mg-AMPPNP'''<br /> | '''Crystal structure of a binary complex of the catalytic subunit of protein kinase CK2 with Mg-AMPPNP'''<br /> | ||
==Overview== | ==Overview== | ||
Protein kinase CK2 (casein kinase 2) is a highly conserved and | 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. | ||
==About this Structure== | ==About this Structure== | ||
1LP4 is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Zea_mays Zea mays] with MG and ANP as [http://en.wikipedia.org/wiki/ligands ligands]. 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:// | 1LP4 is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Zea_mays Zea mays] with <scene name='pdbligand=MG:'>MG</scene> and <scene name='pdbligand=ANP:'>ANP</scene> as [http://en.wikipedia.org/wiki/ligands ligands]. 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=1LP4 OCA]. | ||
==Reference== | ==Reference== | ||
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[[Category: Zea mays]] | [[Category: Zea mays]] | ||
[[Category: Guerra, B.]] | [[Category: Guerra, B.]] | ||
[[Category: Issinger, O | [[Category: Issinger, O G.]] | ||
[[Category: Niefind, K.]] | [[Category: Niefind, K.]] | ||
[[Category: Puetter, M.]] | [[Category: Puetter, M.]] | ||
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[[Category: protein kinase]] | [[Category: protein kinase]] | ||
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Revision as of 14:47, 21 February 2008
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Crystal structure of a binary complex of the catalytic subunit of protein kinase CK2 with Mg-AMPPNP
OverviewOverview
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.
About this StructureAbout this Structure
1LP4 is a Single protein structure of sequence from Zea mays with and as ligands. Active as Non-specific serine/threonine protein kinase, with EC number 2.7.11.1 Full crystallographic information is available from OCA.
ReferenceReference
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:15740749
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