Figure 1.

Primary Structures of CDK12 (Ctk1) family of transcriptional CDK kinases, and Cyclin K.

(a) “Ctk1 family” primary structures aligned by kinase homology domains (dark blue). Purple lines indicate protein “arms” extending from N- and C-termini of kinase domain. Green boxes = RS domains. Gray boxes = Pro- or LeuPro-rich domains. Rust-colored boxes = segments used as immunogens to raise antibodies. (b) Primary structures of human CDKs and Cyclin K (SMART database). Pink boxes = low sequence complexity regions. Letters above pink boxes indicate abundant residues therein. Drawn approx. to scale.