4frf: Difference between revisions
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[[ | ==Structural Studies and Protein Engineering of Inositol Phosphate Multikinase== | ||
<StructureSection load='4frf' size='340' side='right' caption='[[4frf]], [[Resolution|resolution]] 2.90Å' scene=''> | |||
== Structural highlights == | |||
<table><tr><td colspan='2'>[[4frf]] is a 2 chain structure with sequence from [http://en.wikipedia.org/wiki/Arabidopsis_thaliana Arabidopsis thaliana]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=4FRF OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=4FRF FirstGlance]. <br> | |||
</td></tr><tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat"><scene name='pdbligand=SO4:SULFATE+ION'>SO4</scene></td></tr> | |||
<tr id='gene'><td class="sblockLbl"><b>[[Gene|Gene:]]</b></td><td class="sblockDat">At5g07370, AtIpmk alpha, IP3K, IPK2a, IPMK, T2I1.80 ([http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Info&srchmode=5&id=3702 Arabidopsis thaliana])</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=4frf FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=4frf OCA], [http://www.rcsb.org/pdb/explore.do?structureId=4frf RCSB], [http://www.ebi.ac.uk/pdbsum/4frf PDBsum]</span></td></tr> | |||
</table> | |||
<div style="background-color:#fffaf0;"> | |||
== Publication Abstract from PubMed == | |||
Inositol phosphates (IPs) regulate vital processes in eukaryotes, and their production downstream of phospholipase C activation is controlled through a network of evolutionarily conserved kinases and phosphatases. Inositol phosphate multikinase (IPMK, also called Ipk2 and Arg82) accounts for phosphorylation of IP(3) to IP(5), as well as production of several other IP molecules. Here, we report the structure of Arabidopsis thaliana IPMKalpha at 2.9 A and find it is similar to the yeast homolog Ipk2, despite 17% sequence identity, as well as the active site architecture of human IP(3) 3-kinase. Structural comparison and substrate modeling were used to identify a putative basis for IPMK selectivity. To test this model, we re-engineered binding site residues predicted to have restricted substrate specificity. Using steady-state kinetics and in vivo metabolic labeling studies in modified yeast strains, we observed that K117W and K117W:K121W mutants exhibited nearly normal 6-kinase function but harbored significantly reduced 3-kinase activity. These mutants complemented conditional nutritional growth defects observed in ipmk null yeast and, remarkably, suppressed lethality observed in ipmk null flies. Our data are consistent with the hypothesis that IPMK 6-kinase activity and production of Ins(1,4,5,6)P(4) are critical for cellular signaling. Overall, our studies provide new insights into the structure and function of IPMK and utilize a synthetic biological approach to redesign inositol phosphate signaling pathways. | |||
Structural studies and protein engineering of inositol phosphate multikinase.,Endo-Streeter S, Tsui MK, Odom AR, Block J, York JD J Biol Chem. 2012 Oct 12;287(42):35360-9. doi: 10.1074/jbc.M112.365031. Epub 2012, Aug 15. PMID:22896696<ref>PMID:22896696</ref> | |||
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.<br> | |||
</div> | |||
== References == | |||
<references/> | |||
== | __TOC__ | ||
</StructureSection> | |||
[[Category: Arabidopsis thaliana]] | [[Category: Arabidopsis thaliana]] | ||
[[Category: Endo-Streeter, S T | [[Category: Endo-Streeter, S T]] | ||
[[Category: Odom, A R | [[Category: Odom, A R]] | ||
[[Category: Tsui, M | [[Category: Tsui, M]] | ||
[[Category: York, J D | [[Category: York, J D]] | ||
[[Category: Atp grasp]] | [[Category: Atp grasp]] | ||
[[Category: Inositol phosphate kinase]] | [[Category: Inositol phosphate kinase]] | ||
[[Category: Transferase]] | [[Category: Transferase]] | ||
Revision as of 18:47, 9 December 2014
Structural Studies and Protein Engineering of Inositol Phosphate MultikinaseStructural Studies and Protein Engineering of Inositol Phosphate Multikinase
Structural highlights
Publication Abstract from PubMedInositol phosphates (IPs) regulate vital processes in eukaryotes, and their production downstream of phospholipase C activation is controlled through a network of evolutionarily conserved kinases and phosphatases. Inositol phosphate multikinase (IPMK, also called Ipk2 and Arg82) accounts for phosphorylation of IP(3) to IP(5), as well as production of several other IP molecules. Here, we report the structure of Arabidopsis thaliana IPMKalpha at 2.9 A and find it is similar to the yeast homolog Ipk2, despite 17% sequence identity, as well as the active site architecture of human IP(3) 3-kinase. Structural comparison and substrate modeling were used to identify a putative basis for IPMK selectivity. To test this model, we re-engineered binding site residues predicted to have restricted substrate specificity. Using steady-state kinetics and in vivo metabolic labeling studies in modified yeast strains, we observed that K117W and K117W:K121W mutants exhibited nearly normal 6-kinase function but harbored significantly reduced 3-kinase activity. These mutants complemented conditional nutritional growth defects observed in ipmk null yeast and, remarkably, suppressed lethality observed in ipmk null flies. Our data are consistent with the hypothesis that IPMK 6-kinase activity and production of Ins(1,4,5,6)P(4) are critical for cellular signaling. Overall, our studies provide new insights into the structure and function of IPMK and utilize a synthetic biological approach to redesign inositol phosphate signaling pathways. Structural studies and protein engineering of inositol phosphate multikinase.,Endo-Streeter S, Tsui MK, Odom AR, Block J, York JD J Biol Chem. 2012 Oct 12;287(42):35360-9. doi: 10.1074/jbc.M112.365031. Epub 2012, Aug 15. PMID:22896696[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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