Cellular ATP Levels Determine the Stability of a Nucleotide Kinase

The energy currency of the cell ATP, is used by kinases to drive key cellular processes. However, the connection of cellular ATP abundance and protein stability is still under investigation. Using Fast Relaxation Imaging paired with alanine scanning and ATP depletion experiments, we study the nucleotide kinase (APSK) domain of 3′-phosphoadenosine-5′-phosphosulfate (PAPS) synthase, a marginally stable protein. Here, we show that the in-cell stability of the APSK is determined by ligand binding and directly connected to cellular ATP levels. The observed protein stability change for different ligand-bound states or under ATP-depleted conditions ranges from ΔGf0 = -10.7 to +13.8 kJ/mol, which is remarkable since it exceeds changes measured previously, for example upon osmotic pressure, cellular stress or differentiation. The results have implications for protein stability during the catalytic cycle of APS kinase and suggest that the cellular ATP level functions as a global regulator of kinase activity.

Detection of T4 polynucleotide kinase based on a MnO2nanosheet-3,3′,5,5′-tetramethylbenzidine (TMB) colorimetric system

Determination of nucleotide kinase activity is valuable due to its importance in regulating nucleic acid metabolism.

Development of a highly sensitive sensing platform for T4 polynucleotide kinase phosphatase and its inhibitors based on WS2 nanosheets

A novel strategy for nucleotide kinase phosphatase activity assay based on WS2 nanosheets.