2I53
Crystal structure of Cyclin K
Summary for 2I53
| Entry DOI | 10.2210/pdb2i53/pdb |
| Related | 1BU2 1JKW 1KXU 1VIN |
| Descriptor | Cyclin K, ACETATE ION (3 entities in total) |
| Functional Keywords | cell cycle, transcription, cyclin k, cyclin box, cdk9, positive transcription elongation factor, p-tefb |
| Biological source | Homo sapiens (human) |
| Total number of polymer chains | 1 |
| Total formula weight | 30459.06 |
| Authors | Baek, K.,Brown, R.S.,Birrane, G.,Ladias, J.A.A. (deposition date: 2006-08-23, release date: 2007-01-02, Last modification date: 2024-02-21) |
| Primary citation | Baek, K.,Brown, R.S.,Birrane, G.,Ladias, J.A. Crystal Structure of Human Cyclin K, a Positive Regulator of Cyclin-dependent Kinase 9. J.Mol.Biol., 366:563-573, 2007 Cited by PubMed Abstract: 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. PubMed: 17169370DOI: 10.1016/j.jmb.2006.11.057 PDB entries with the same primary citation |
| Experimental method | X-RAY DIFFRACTION (1.5 Å) |
Structure validation
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