4CXA

Crystal structure of the human CDK12-cyclin K complex bound to AMPPNP

Summary for 4CXA

• Entry DOI: 10.2210/pdb4cxa/pdb
• Descriptor: CYCLIN-DEPENDENT KINASE 12, CYCLIN-K, PHOSPHOAMINOPHOSPHONIC ACID-ADENYLATE ESTER (3 entities in total)
• Functional Keywords: transferase, kinase
• Biological source: HOMO SAPIENS (HUMAN); More
• Cellular location: Nucleus: Q9NYV4 O75909
• Total number of polymer chains: 4
• Total formula weight: 140832.34

Authors

Dixon Clarke, S.E.,Elkins, J.M.,Pike, A.C.W.,Nowak, R.,Goubin, S.,Mahajan, R.P.,Kopec, J.,Froese, S.,Tallant, C.,Carpenter, E.P.,Mackenzie, A.,Faust, B.,Burgess-Brown, N.,von Delft, F.,Arrowsmith, C.,Edwards, A.M.,Bountra, C.,Bullock, A. (deposition date: 2014-04-04, release date: 2014-05-21, Last modification date: 2024-10-16)

Primary citation

Dixon-Clarke, S.E.,Elkins, J.M.,Cheng, S.G.,Morin, G.B.,Bullock, A.N.
Structures of the Cdk12/Cyck Complex with AMP-Pnp Reveal a Flexible C-Terminal Kinase Extension Important for ATP Binding.
Sci.Rep., 5:17122-, 2015

PubMed Abstract: Cyclin-dependent kinase 12 (CDK12) promotes transcriptional elongation by phosphorylation of the RNA polymerase II C-terminal domain (CTD). Structure-function studies show that this activity is dependent on a C-terminal kinase extension, as well as the binding of cyclin K (CycK). To better define these interactions we determined the crystal structure of the human CDK12/CycK complex with and without the kinase extension in the presence of AMP-PNP. The structures revealed novel features for a CDK, including a large β4-β5 loop insertion that contributes to the N-lobe interaction with the cyclin. We also observed two different conformations of the C-terminal kinase extension that effectively open and close the ATP pocket. Most notably, bound AMP-PNP was only observed when trapped in the closed state. Truncation of this C-terminal structure also diminished AMP-PNP binding, as well as the catalytic activity of the CDK12/CycK complex. Further kinetic measurements showed that the full length CDK12/CycK complex was significantly more active than the two crystallised constructs suggesting a critical role for additional domains. Overall, these results demonstrate the intrinsic flexibility of the C-terminal extension in CDK12 and highlight its importance for both ATP binding and kinase activity.

PubMed: 26597175
DOI: 10.1038/SREP17122

Experimental method

X-RAY DIFFRACTION (3.15 Å)