View source for 1kxu


==CYCLIN H, A POSITIVE REGULATORY SUBUNIT OF CDK ACTIVATING KINASE==
<StructureSection load='1kxu' size='340' side='right'caption='[[1kxu]], [[Resolution|resolution]] 2.60&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[1kxu]] is a 1 chain structure with sequence from [https://en.wikipedia.org/wiki/Human Human]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1KXU OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1KXU FirstGlance]. <br>
</td></tr><tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[https://proteopedia.org/fgij/fg.htm?mol=1kxu FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1kxu OCA], [https://pdbe.org/1kxu PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=1kxu RCSB], [https://www.ebi.ac.uk/pdbsum/1kxu PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=1kxu ProSAT]</span></td></tr>
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== Function ==
[[https://www.uniprot.org/uniprot/CCNH_HUMAN CCNH_HUMAN]] Regulates CDK7, the catalytic subunit of the CDK-activating kinase (CAK) enzymatic complex. CAK activates the cyclin-associated kinases CDK1, CDK2, CDK4 and CDK6 by threonine phosphorylation. CAK complexed to the core-TFIIH basal transcription factor activates RNA polymerase II by serine phosphorylation of the repetitive C-terminus domain (CTD) of its large subunit (POLR2A), allowing its escape from the promoter and elongation of the transcripts. Involved in cell cycle control and in RNA transcription by RNA polymerase II. Its expression and activity are constant throughout the cell cycle.<ref>PMID:7533895</ref> <ref>PMID:10024882</ref>  
== Evolutionary Conservation ==
[[Image:Consurf_key_small.gif|200px|right]]
Check<jmol>
  <jmolCheckbox>
    <scriptWhenChecked>; select protein; define ~consurf_to_do selected; consurf_initial_scene = true; script "/wiki/ConSurf/kx/1kxu_consurf.spt"</scriptWhenChecked>
    <scriptWhenUnchecked>script /wiki/extensions/Proteopedia/spt/initialview01.spt</scriptWhenUnchecked>
    <text>to colour the structure by Evolutionary Conservation</text>
  </jmolCheckbox>
</jmol>, as determined by [http://consurfdb.tau.ac.il/ ConSurfDB]. You may read the [[Conservation%2C_Evolutionary|explanation]] of the method and the full data available from [http://bental.tau.ac.il/new_ConSurfDB/main_output.php?pdb_ID=1kxu ConSurf].
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== Publication Abstract from PubMed ==
Cyclin-dependent kinases (CDKs), which play a key role in cell cycle control, are activated by the CDK activating kinase (CAK), which activates cyclin-bound CDKs by phosphorylation at a specific threonine residue. Vertebrate CAK contains two key components: a kinase subunit with homology to its substrate CDKs and a regulatory subunit with homology to cyclins. We have determined the X-ray crystal structure of the regulatory subunit of CAK, cyclin H, at 2.6 A resolution. Cyclin H contains two alpha-helical core domains with a fold similar to that of cyclin A, a regulatory subunit of CAK substrate CDK2, and of TFIIB, a transcription factor. Outside of the core domains, the N- and C-terminal regions of the three structures are completely different. The conformational differences between cyclin H and A structures may reflect functional differences between the two cyclins.

Three-dimensional structure of human cyclin H, a positive regulator of the CDK-activating kinase.,Kim KK, Chamberlin HM, Morgan DO, Kim SH Nat Struct Biol. 1996 Oct;3(10):849-55. PMID:8836101<ref>PMID:8836101</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
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==See Also==
*[[Cyclin 3D structures|Cyclin 3D structures]]
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Human]]
[[Category: Large Structures]]
[[Category: Chamberin, H M]]
[[Category: Kim, K K]]
[[Category: Kim, S H]]
[[Category: Morgan, D O]]
[[Category: Alpha-helical structure]]
[[Category: Cell cycle]]
[[Category: Cell division]]
[[Category: Cyclin]]
[[Category: Nuclear protein]]
[[Category: Regulatory protein]]