6xx6
Arabidopsis thaliana Casein Kinase 2 (CK2) alpha-1 crystal form I
Structural highlights
FunctionCSK21_ARATH Casein kinases are operationally defined by their preferential utilization of acidic proteins such as caseins as substrates. Phosphorylates casein in vitro (PubMed:7678767). The alpha chain contains the catalytic site. The tetrameric holoenzyme CK2, composed of two alpha and two beta subunits, phosphorylates the transcription factor GBFl, resulting in stimulation of its DNA binding activity (PubMed:7696877). CK2 phosphorylates the transcription factor PIF1 after an exposure to light, resulting in a proteasome-dependent degradation of PIF1 and promotion of photomorphogenesis (PubMed:21330376). CK2 phosphorylates translation initiation factors. May participate in the regulation of the initiation of translation (PubMed:19509278, PubMed:19509420). Acts as circadian clock component that maintains the correct period length through phosphorylation of CCA1 (PubMed:21900482). Required for the maintenance and control of genomic stability and chromatin structure (PubMed:22487192). May act as an ectokinase that phosphorylates several extracellular proteins.[1] [2] [3] [4] [5] [6] [7] Publication Abstract from PubMedCasein kinase 2 (CK2) is a ubiquitous pleiotropic enzyme that is highly conserved across eukaryotic kingdoms. CK2 is singular amongst kinases as it is highly rigid and constitutively active. Arabidopsis thaliana is widely used as a model system in molecular plant research; the biological functions of A. thaliana CK2 are well studied in vivo and many of its substrates have been identified. Here, crystal structures of the alpha subunit of A. thaliana CK2 in three crystal forms and of its complex with the nonhydrolyzable ATP analog AMppNHp are presented. While the C-lobe of the enzyme is highly rigid, structural plasticity is observed for the N-lobe. Small but significant displacements within the active cleft are necessary in order to avoid steric clashes with the AMppNHp molecule. Binding of AMppNHp is influenced by a rigid-body motion of the N-lobe that was not previously recognized in maize CK2. Crystal structure of Arabidopsis thaliana casein kinase 2 alpha1.,Demulder M, De Veylder L, Loris R Acta Crystallogr F Struct Biol Commun. 2020 Apr 1;76(Pt 4):182-191. doi:, 10.1107/S2053230X20004537. Epub 2020 Apr 6. PMID:32254052[8] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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