User:Alice Harmon/Sandbox 2: Difference between revisions

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==CDPK==
==CDPK==


Calcium-dependent protein kinases (CDPKs) are found in plants, algae, and apicomplexan protists, such as the parasites that cause malaria and toxoplasmosis. They are monomeric enzymes containing an amino-terminal protein kinase domain linked to a carboxy-terminal calcium-binding domain, that has sequence similarity to calmodulin. CDPKs belong to the calmodulin-dependent protein kinase family.  
Calcium-dependent protein kinases (CDPKs) are found in plants, green algae, and protists. In plants CDPKs are encoded by large gene families<ref> PMCID:PMC167006</ref><ref>PMID:17172291</ref> and they are involved in many cellular responses to stimuli such as hormones. In the apicomplexan protists ''Plasmodium falciparum''(parasite that causes malaria) and ''Toxoplasma gondii''(parasite that causes toxoplasmosis), CDPKs are encoded by small gene families and they are involved in critical stages of the parasite life cycle <ref>PMCID:PMC3514314</ref><ref>PMID:20466936.
 
CDPKs are monomeric enzymes containing an amino-terminal protein kinase domain linked to a carboxy-terminal calcium-binding regulatory domain, which has sequence similarity to calmodulin, and they belong to the calmodulin-dependent protein kinase family<ref>PMCID:1852075</ref>. CDPKs are regulated by the binding of calcium to the regulatory domain, and thus are activated in processes that elevate the concentration of calcium inside cells.  


Crystal structures of inactive and active conformations of CDPK1 from ''Toxoplasma gondii'' show the dramatic conformation change that occurs upon the binding of calcium to the regulatory domain <ref> PMID:20436473 </ref>.
Crystal structures of inactive and active conformations of CDPK1 from ''Toxoplasma gondii'' show the dramatic conformation change that occurs upon the binding of calcium to the regulatory domain <ref> PMID:20436473 </ref>.

Revision as of 20:46, 18 September 2013

CDPKCDPK

Calcium-dependent protein kinases (CDPKs) are found in plants, green algae, and protists. In plants CDPKs are encoded by large gene families[1][2] and they are involved in many cellular responses to stimuli such as hormones. In the apicomplexan protists Plasmodium falciparum(parasite that causes malaria) and Toxoplasma gondii(parasite that causes toxoplasmosis), CDPKs are encoded by small gene families and they are involved in critical stages of the parasite life cycle [3]Cite error: Closing </ref> missing for <ref> tag. CDPKs are regulated by the binding of calcium to the regulatory domain, and thus are activated in processes that elevate the concentration of calcium inside cells.

Crystal structures of inactive and active conformations of CDPK1 from Toxoplasma gondii show the dramatic conformation change that occurs upon the binding of calcium to the regulatory domain [4].

3hx4 - active TgCDPK1

Drag the structure with the mouse to rotate

3ku2 - inactive TgCDPK1

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Dummy scenes


Dummy scenes


The crystal structure 3hx4 in the left scene shows the active conformation of the kinase that is bound to calcium (green spheres) and the ATP analog ANP (also called AMPPNP; shown in wireframe and CPK coloring). The catalytic domain is blue and the calcium activation domain (CAD) is gold. In the kinase domain, ANP sits in the catalytic cleft between the large and small lobes of the domain. CAD is bound to the side of the kinase opposite to the catalytic cleft, making it available for peptide substrate binding. The crystal structure 3ku2 in the right scene shows the inactive conformation of the kinase that is bound only to the ANP (wireframe and CPK coloring). As above, the catalytic domain is blue and the CAD is gold. The large lobe of the kinase domain is in approximately the same orientation as in the left scene. Note the large conformational change in the CAD (long alpha helices) and that it is now bound to the same side of the kinase as the catalytic cleft (marked by the bound ANP), blocking it from binding peptide substrate.

ReferencesReferences

  1. PMCID:PMC167006
  2. Dardick C, Chen J, Richter T, Ouyang S, Ronald P. The rice kinase database. A phylogenomic database for the rice kinome. Plant Physiol. 2007 Feb;143(2):579-86. Epub 2006 Dec 15. PMID:17172291 doi:10.1104/pp.106.087270
  3. PMCID:PMC3514314
  4. Wernimont AK, Artz JD, Finerty P Jr, Lin YH, Amani M, Allali-Hassani A, Senisterra G, Vedadi M, Tempel W, Mackenzie F, Chau I, Lourido S, Sibley LD, Hui R. Structures of apicomplexan calcium-dependent protein kinases reveal mechanism of activation by calcium. Nat Struct Mol Biol. 2010 May;17(5):596-601. Epub 2010 May 2. PMID:20436473 doi:10.1038/nsmb.1795