2i53

<table><tr><td colspan='2'>[[2i53]] 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=2I53 OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=2I53 FirstGlance]. <br>

</td></tr><tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=ACT:ACETATE+ION'>ACT</scene></td></tr>

<tr id='related'><td class="sblockLbl"><b>[[Related_structure|Related:]]</b></td><td class="sblockDat"><div style='overflow: auto; max-height: 3em;'>[[1jkw|1jkw]], [[1kxu|1kxu]], [[1vin|1vin]], [[1bu2|1bu2]]</div></td></tr>

<tr id='gene'><td class="sblockLbl"><b>[[Gene|Gene:]]</b></td><td class="sblockDat">CCNK ([https://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Info&srchmode=5&id=9606 HUMAN])</td></tr>

[[https://www.uniprot.org/uniprot/CCNK_HUMAN CCNK_HUMAN]] May play a role in transcriptional regulation. In vitro, is associated with a kinase activity toward both RNA polymerase II C-terminal domain and CDK2 (CAK).<ref>PMID:10574912</ref>

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== Publication Abstract from PubMed ==

Cyclin K and the closely related cyclins T1, T2a, and T2b interact with cyclin-dependent kinase 9 (CDK9) forming multiple nuclear complexes, referred to collectively as positive transcription elongation factor b (P-TEFb). Through phosphorylation of the C-terminal domain of the RNA polymerase II largest subunit, distinct P-TEFb species regulate the transcriptional elongation of specific genes that play central roles in human physiology and disease development, including cardiac hypertrophy and human immunodeficiency virus-1 pathogenesis. We have determined the crystal structure of human cyclin K (residues 11-267) at 1.5 A resolution, which represents the first atomic structure of a P-TEFb subunit. The cyclin K fold comprises two typical cyclin boxes with two short helices preceding the N-terminal box. A prominent feature of cyclin K is an additional helix (H4a) in the first cyclin box that obstructs the binding pocket for the cell-cycle inhibitor p27(Kip1). Modeling of CDK9 bound to cyclin K provides insights into the structural determinants underlying the formation and regulation of this complex. A homology model of human cyclin T1 generated using the cyclin K structure as a template reveals that the two proteins have similar structures, as expected from their high level of sequence identity. Nevertheless, their CDK9-interacting surfaces display significant structural differences, which could potentially be exploited for the design of cyclin-targeted inhibitors of the CDK9-cyclin K and CDK9-cyclin T1 complexes.

Crystal structure of human cyclin K, a positive regulator of cyclin-dependent kinase 9.,Baek K, Brown RS, Birrane G, Ladias JA J Mol Biol. 2007 Feb 16;366(2):563-73. Epub 2006 Nov 18. PMID:17169370<ref>PMID:17169370</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>

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<div class="pdbe-citations 2i53" style="background-color:#fffaf0;"></div>

[[Category: Human]]

[[Category: Baek, K]]

[[Category: Birrane, G]]

[[Category: Brown, R S]]

[[Category: Ladias, J A.A]]

[[Category: Transcription]]