2i53
From Proteopedia
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| , resolution 1.50Å | |||||||
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| Ligands: | |||||||
| Gene: | CCNK (Homo sapiens) | ||||||
| Related: | 1JKW, 1KXU, 1VIN, 1BU2
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| Resources: | FirstGlance, OCA, PDBsum, RCSB | ||||||
| Coordinates: | save as pdb, mmCIF, xml | ||||||
Crystal structure of Cyclin K
Overview
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.
About this Structure
2I53 is a Single protein structure of sequence from Homo sapiens. Full crystallographic information is available from OCA.
Reference
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
Page seeded by OCA on Mon Mar 31 03:39:53 2008
