Sugiura H, Yamauchi T
Department of Cell Biology, Tokyo Metropolitan Institute for Neuroscience, Japan.
Biochim Biophys Acta. 1993 Jun 30;1177(3):270-4. doi: 10.1016/0167-4889(93)90122-6.
Binding of Ca2+/calmodulin-dependent protein kinase II (CaM kinase II) with calmodulin was directly determined by the poly(ethylene glycol) precipitation method. Calmodulin bound to CaM kinase II alpha and beta polypeptides in a molar ratio of about 1:1 in the presence of ATP, but the binding was reduced in the absence of ATP. Affinity of CaM kinase II for calmodulin increased in the presence of ATP and the autophosphorylation was observed under the conditions. ADP and adenosine beta, gamma-imidoadenosine 5'-triphosphate, hydrolysis resistant analogues, also increased the binding of CaM kinase II with calmodulin. CaM kinase II substrate syntide 2 did not increase the binding of the kinase with calmodulin. These findings indicate that the affinity of CaM kinase II for calmodulin and the amount of calmodulin bound to the kinase increase by the binding of ATP.
采用聚乙二醇沉淀法直接测定了Ca2+/钙调蛋白依赖性蛋白激酶II（CaM激酶II）与钙调蛋白的结合情况。在ATP存在的情况下，钙调蛋白以约1:1的摩尔比与CaM激酶II的α和β多肽结合，但在无ATP时结合减少。在ATP存在的情况下，CaM激酶II对钙调蛋白的亲和力增加，并且在这些条件下观察到了自身磷酸化。ADP以及腺苷β,γ-亚氨基腺苷5'-三磷酸（一种抗水解类似物）也增加了CaM激酶II与钙调蛋白的结合。CaM激酶II的底物合成肽2并未增加该激酶与钙调蛋白的结合。这些发现表明，ATP的结合增加了CaM激酶II对钙调蛋白的亲和力以及与该激酶结合的钙调蛋白的量。
