4dh3: Difference between revisions
No edit summary |
No edit summary |
||
| Line 1: | Line 1: | ||
==Low temperature X-ray structure of cAMP dependent Protein Kinase A catalytic subunit with high Mg2+, ATP and IP20== | |||
<StructureSection load='4dh3' size='340' side='right' caption='[[4dh3]], [[Resolution|resolution]] 2.20Å' scene=''> | |||
== Structural highlights == | |||
<table><tr><td colspan='2'>[[4dh3]] is a 2 chain structure with sequence from [http://en.wikipedia.org/wiki/Mus_musculus Mus musculus]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=4DH3 OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=4DH3 FirstGlance]. <br> | |||
</td></tr><tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat"><scene name='pdbligand=ATP:ADENOSINE-5-TRIPHOSPHATE'>ATP</scene>, <scene name='pdbligand=MG:MAGNESIUM+ION'>MG</scene></td></tr> | |||
<tr id='NonStdRes'><td class="sblockLbl"><b>[[Non-Standard_Residue|NonStd Res:]]</b></td><td class="sblockDat"><scene name='pdbligand=SEP:PHOSPHOSERINE'>SEP</scene>, <scene name='pdbligand=TPO:PHOSPHOTHREONINE'>TPO</scene></td></tr> | |||
<tr id='related'><td class="sblockLbl"><b>[[Related_structure|Related:]]</b></td><td class="sblockDat">[[4dh1|4dh1]], [[4dh5|4dh5]], [[4dh7|4dh7]], [[4dh8|4dh8]]</td></tr> | |||
<tr id='gene'><td class="sblockLbl"><b>[[Gene|Gene:]]</b></td><td class="sblockDat">Prkaca, Pkaca ([http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Info&srchmode=5&id=10090 Mus musculus])</td></tr> | |||
<tr id='activity'><td class="sblockLbl"><b>Activity:</b></td><td class="sblockDat"><span class='plainlinks'>[http://en.wikipedia.org/wiki/cAMP-dependent_protein_kinase cAMP-dependent protein kinase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=2.7.11.11 2.7.11.11] </span></td></tr> | |||
<tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=4dh3 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=4dh3 OCA], [http://www.rcsb.org/pdb/explore.do?structureId=4dh3 RCSB], [http://www.ebi.ac.uk/pdbsum/4dh3 PDBsum]</span></td></tr> | |||
</table> | |||
<div style="background-color:#fffaf0;"> | |||
== Publication Abstract from PubMed == | |||
Post-translational protein phosphorylation by protein kinase A (PKA) is a ubiquitous signalling mechanism which regulates many cellular processes. A low-temperature X-ray structure of the ternary complex of the PKA catalytic subunit (PKAc) with ATP and a 20-residue peptidic inhibitor (IP20) at the physiological Mg(2+) concentration of approximately 0.5 mM (LT PKA-MgATP-IP20) revealed a single metal ion in the active site. The lack of a second metal in LT PKA-MgATP-IP20 renders the beta- and gamma-phosphoryl groups of ATP very flexible, with high thermal B factors. Thus, the second metal is crucial for tight positioning of the terminal phosphoryl group for transfer to a substrate, as demonstrated by comparison of the former structure with that of the LT PKA-Mg(2)ATP-IP20 complex obtained at high Mg(2+) concentration. In addition to its kinase activity, PKAc is also able to slowly catalyze the hydrolysis of ATP using a water molecule as a substrate. It was found that ATP can be readily and completely hydrolyzed to ADP and a free phosphate ion in the crystals of the ternary complex PKA-Mg(2)ATP-IP20 by X-ray irradiation at room temperature. The cleavage of ATP may be aided by X-ray-generated free hydroxyl radicals, a very reactive chemical species, which move rapidly through the crystal at room temperature. The phosphate anion is clearly visible in the electron-density maps; it remains in the active site but slides about 2 A from its position in ATP towards Ala21 of IP20, which mimics the phosphorylation site. The phosphate thus pushes the peptidic inhibitor away from the product ADP, while resulting in dramatic conformational changes of the terminal residues 24 and 25 of IP20. X-ray structures of PKAc in complex with the nonhydrolysable ATP analogue AMP-PNP at both room and low temperature demonstrated no temperature effects on the conformation and position of IP20. | |||
Low- and room-temperature X-ray structures of protein kinase A ternary complexes shed new light on its activity.,Kovalevsky AY, Johnson H, Hanson BL, Waltman MJ, Fisher SZ, Taylor S, Langan P Acta Crystallogr D Biol Crystallogr. 2012 Jul;68(Pt 7):854-60. doi:, 10.1107/S0907444912014886. Epub 2012 Jun 15. PMID:22751671<ref>PMID:22751671</ref> | |||
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.<br> | |||
</div> | |||
==See Also== | |||
*[[CAMP-dependent protein kinase|CAMP-dependent protein kinase]] | |||
== References == | |||
<references/> | |||
__TOC__ | |||
</StructureSection> | |||
[[Category: Mus musculus]] | [[Category: Mus musculus]] | ||
[[Category: CAMP-dependent protein kinase]] | [[Category: CAMP-dependent protein kinase]] | ||
[[Category: Kovalevsky, A Y | [[Category: Kovalevsky, A Y]] | ||
[[Category: Langan, P | [[Category: Langan, P]] | ||
[[Category: Atp and peptidic inhibitor]] | [[Category: Atp and peptidic inhibitor]] | ||
[[Category: Phosphorylation]] | [[Category: Phosphorylation]] | ||
[[Category: Protein]] | [[Category: Protein]] | ||
[[Category: Transferase-transferase inhibitor complex]] | [[Category: Transferase-transferase inhibitor complex]] | ||
Revision as of 11:44, 18 December 2014
Low temperature X-ray structure of cAMP dependent Protein Kinase A catalytic subunit with high Mg2+, ATP and IP20Low temperature X-ray structure of cAMP dependent Protein Kinase A catalytic subunit with high Mg2+, ATP and IP20
Structural highlights
Publication Abstract from PubMedPost-translational protein phosphorylation by protein kinase A (PKA) is a ubiquitous signalling mechanism which regulates many cellular processes. A low-temperature X-ray structure of the ternary complex of the PKA catalytic subunit (PKAc) with ATP and a 20-residue peptidic inhibitor (IP20) at the physiological Mg(2+) concentration of approximately 0.5 mM (LT PKA-MgATP-IP20) revealed a single metal ion in the active site. The lack of a second metal in LT PKA-MgATP-IP20 renders the beta- and gamma-phosphoryl groups of ATP very flexible, with high thermal B factors. Thus, the second metal is crucial for tight positioning of the terminal phosphoryl group for transfer to a substrate, as demonstrated by comparison of the former structure with that of the LT PKA-Mg(2)ATP-IP20 complex obtained at high Mg(2+) concentration. In addition to its kinase activity, PKAc is also able to slowly catalyze the hydrolysis of ATP using a water molecule as a substrate. It was found that ATP can be readily and completely hydrolyzed to ADP and a free phosphate ion in the crystals of the ternary complex PKA-Mg(2)ATP-IP20 by X-ray irradiation at room temperature. The cleavage of ATP may be aided by X-ray-generated free hydroxyl radicals, a very reactive chemical species, which move rapidly through the crystal at room temperature. The phosphate anion is clearly visible in the electron-density maps; it remains in the active site but slides about 2 A from its position in ATP towards Ala21 of IP20, which mimics the phosphorylation site. The phosphate thus pushes the peptidic inhibitor away from the product ADP, while resulting in dramatic conformational changes of the terminal residues 24 and 25 of IP20. X-ray structures of PKAc in complex with the nonhydrolysable ATP analogue AMP-PNP at both room and low temperature demonstrated no temperature effects on the conformation and position of IP20. Low- and room-temperature X-ray structures of protein kinase A ternary complexes shed new light on its activity.,Kovalevsky AY, Johnson H, Hanson BL, Waltman MJ, Fisher SZ, Taylor S, Langan P Acta Crystallogr D Biol Crystallogr. 2012 Jul;68(Pt 7):854-60. doi:, 10.1107/S0907444912014886. Epub 2012 Jun 15. PMID:22751671[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
|
| ||||||||||||||||||||||||