This old version of Proteopedia is provided for student assignments while the new version is undergoing repairs. Content and edits done in this old version of Proteopedia after March 1, 2026 will eventually be lost when it is retired in about June of 2026.

Apply for new accounts at the new Proteopedia. Your logins will work in both the old and new versions.

4da5

From Proteopedia

(Difference between revisions)

Jump to: navigation, search

Revision as of 02:31, 13 July 2016

Choline Kinase alpha acts through a double-displacement kinetic mechanism involving enzyme isomerisation, as determined through enzyme and inhibitor kinetics and structural biology

Structural highlights

4da5 is a 2 chain structure with sequence from Human. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance.
Ligands:	,
Gene:	CHKA, CHK, CKI (HUMAN)
Resources:	FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT

Function

[CHKA_HUMAN] Has a key role in phospholipid biosynthesis and may contribute to tumor cell growth. Catalyzes the first step in phosphatidylcholine biosynthesis. Contributes to phosphatidylethanolamine biosynthesis. Phosphorylates choline and ethanolamine. Has higher activity with choline.^[1]

Publication Abstract from PubMed

Choline Kinase is a key component of the Kennedy pathway that converts choline into a number of structural and signalling lipids that are essential for cell growth and survival. One member of the family, Choline Kinase-alpha (ChoKalpha) is frequently up-regulated in human cancers, and expression of ChoKalpha is sufficient to transform cells. Consequently ChoKalpha has been studied as a potential target for therapeutic agents in cancer research. Despite great interest in the enzyme, mechanistic studies have not been reported. In this study, a combination of initial velocity and product inhibition studies, together with the kinetic and structural characterisation of a novel ChoKalpha inhibitor is used to support a mechanism of action for human ChoKalpha. Substrate and inhibition kinetics are consistent with an iso double displacement mechanism, in which the gamma-phosphate from ATP is transferred to choline in two distinct steps via a phospho-enzyme intermediate. Co-crystal structures, and existing site-specific mutation studies, support an important role for Asp306, in stabilising the phospho-enzyme intermediate. The kinetics also indicate a distinct kinetic (isomerisation) step associated with product release, which may be attributed to a conformational change in the protein to disrupt an interaction between Asp306 and the phosphocholine product, facilitating product release. This study describes a mechanism for ChoKalpha that is unusual amongst kinases, and highlights the availability of different enzyme states that can be exploited for drug discovery.

Kinetic and mechanistic characterisation of Choline Kinase-alpha.,Hudson CS, Knegtel RM, Brown K, Charlton PA, Pollard JR Biochim Biophys Acta. 2013 Jun;1834(6):1107-16. doi:, 10.1016/j.bbapap.2013.02.008. Epub 2013 Feb 13. PMID:23416529^[2]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

References

↑ Gallego-Ortega D, Ramirez de Molina A, Ramos MA, Valdes-Mora F, Barderas MG, Sarmentero-Estrada J, Lacal JC. Differential role of human choline kinase alpha and beta enzymes in lipid metabolism: implications in cancer onset and treatment. PLoS One. 2009 Nov 12;4(11):e7819. doi: 10.1371/journal.pone.0007819. PMID:19915674 doi:10.1371/journal.pone.0007819
↑ Hudson CS, Knegtel RM, Brown K, Charlton PA, Pollard JR. Kinetic and mechanistic characterisation of Choline Kinase-alpha. Biochim Biophys Acta. 2013 Jun;1834(6):1107-16. doi:, 10.1016/j.bbapap.2013.02.008. Epub 2013 Feb 13. PMID:23416529 doi:10.1016/j.bbapap.2013.02.008

1 Structural highlights
2 Function
3 Publication Abstract from PubMed
4 See Also
5 References

Proteopedia Page Contributors and Editors (what is this?)

OCA

Retrieved from "http://52.214.119.220/wiki/index.php/4da5"

@@ Line 6: / Line 6: @@
 </td></tr><tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat"><scene name='pdbligand=0H7:(3R)-1-AZABICYCLO[2.2.2]OCT-3-YL[BIS(5-CHLOROTHIOPHEN-2-YL)]METHANOL'>0H7</scene>, <scene name='pdbligand=SO4:SULFATE+ION'>SO4</scene></td></tr>
 <tr id='gene'><td class="sblockLbl"><b>[[Gene|Gene:]]</b></td><td class="sblockDat">CHKA, CHK, CKI ([http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Info&srchmode=5&id=9606 HUMAN])</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=4da5 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=4da5 OCA], [http://pdbe.org/4da5 PDBe], [http://www.rcsb.org/pdb/explore.do?structureId=4da5 RCSB], [http://www.ebi.ac.uk/pdbsum/4da5 PDBsum]</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=4da5 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=4da5 OCA], [http://pdbe.org/4da5 PDBe], [http://www.rcsb.org/pdb/explore.do?structureId=4da5 RCSB], [http://www.ebi.ac.uk/pdbsum/4da5 PDBsum], [http://prosat.h-its.org/prosat/prosatexe?pdbcode=4da5 ProSAT]</span></td></tr>
 </table>
 == Function ==

4da5

From Proteopedia

Revision as of 02:31, 13 July 2016

Choline Kinase alpha acts through a double-displacement kinetic mechanism involving enzyme isomerisation, as determined through enzyme and inhibitor kinetics and structural biology

Structural highlights

Function

Publication Abstract from PubMed

See Also

References

Contents

Proteopedia Page Contributors and Editors (what is this?)

Views

Personal tools

Navigation

Search

Toolbox