Effect of phosphorylation of calmodulin on calcium binding affinity as estimated by terbium fluorescence.
The effect of phosphorylation of calmodulin by casein kinase 2 on the calcium binding of the former was studied by measurement of terbium fluorescence. The binding of Tb3+ to calmodulin was followed by an increase in Tb3+ fluorescence at 545 nm. The terbium fluorescence of phosphorylated calmodulin increased at a lower concentration of Tb3+ than that of non-phosphorylated calmodulin, indicating that Tb3+ binding affinity of calmodulin was increased by phosphorylation. Our results suggest that the interaction between calcium and binding domain becomes stronger by phosphorylation.
Aiuchi
T
T
Laboratory of Biological Chemistry, School of Pharmaceutical Sciences, Showa University, Tokyo, Japan.
Hagiwara
T
T
Omata
K
K
Nakaya
K
K
Nakamura
Y
Y
D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D001667:Binding, Competitive; D002118:Calcium / Q000032:analysis / Q000037:antagonists & inhibitors / Q000378:metabolism; D002147:Calmodulin / Q000378:metabolism*; D047388:Casein Kinases; D002417:Cattle; D005453:Fluorescence; D010766:Phosphorylation; D011485:Protein Binding / Q000502:physiology; D011494:Protein Kinases / Q000378:metabolism; D013050:Spectrometry, Fluorescence; D013725:Terbium / Q000378:metabolism
D002147:Calmodulin; D013725:Terbium; D000255:Adenosine Triphosphate; D011494:Protein Kinases; D047388:Casein Kinases; D002118:Calcium